BODY ORGANIZATION

Anatomical position and terms of direction 1

KAPLAJ.4) MEDICAL .......

a A

`I b

1. Anatomical position and terms of direction

a. Superior or cranial

e. Proximal b. Inferior or caudal

1. Distal c. Lateral

g. Posterior (dorsal) d. Medial

h. Anterior (ventral)

The position of structures within the body, and movement of body parts, is described by this set of terms and always refers to the position of the structure if the individual were standing in the position shown here. The head area is designated by the term cranial, referring to a term for the bones of the skull, while the opposite end of the body is caudal, referring to the tail. Cranial and caudal are synonymous with the terms superior and Inferior, respectively, indicating that a structure is higher or lower. Medial is toward the vertical midline of the body, while lateral is away from the midline. In the limbs, structures near the trunk are proximal, while those further from the trunk are distal. Anterior denotes the "front" of the body (in the direction of travel) while posterior is opposite. In humans, ventral (toward the belly) is equivalent to anterior, while dorsal is the same as posterior. Not shown in the illustration, superficial is near the body surface while deep refers to structures away from the body surface.

■

2 Anatomical planes of the body

KAPLAN) MEDICAL ".....

2. Anatomical planes of the body

a. Frontal (coronal) plane b. Transverse (horizontal)

plane c. Median (midsagittal) plane

Planes of section are used in des cribing anatomical positions of structures. The three planes are perpendicular to one another, and provide a way to show a two •d imensional aspect of a three-dimensional individual. If you were to figu ratively slice completely through the body from head to foot, cutting it into left and right portions, this would be a sagittal section. The mid sagittal plane, or median plane, divides the individual into equal halt' es, while other sagittal sections are parallel to that. A frontal or coro nal plane splits the organism into front and back portions (coronal is usually reserved for planes that pass through the skull), while a tra nsverse or horizontal plane cuts parallel to the ground, creating up per (cranial) and lower (caudal) portions.

3. Anterior regions of the body

a. Head b. Neck (cervical) c. Deltoid d. Sternal e. Pectoral (chest) 1. Brachial (arm) g. Cubital h. Abdominal I. Antebrachial (forearm)

j. Trochanteric k. Palmar L Digital (fingers) m. Inguinal and pubic n. Penis (genital) o. Femoral (thigh) p. Knee q. Lig r. Dorsal foot

The head is connected to the trunk through the cervical or neck region. The trunk includes the chest and sternal regions, the abdomen, and the inguinal/pubic and genital regions (the penis, of course, is an organ that is only found in the male). The upper limbs may be divided into the deltoid (shoulder), brachial (upper arm), cubital (front of elbow), antebrachial (lower arm), palmar (hand) and digital (fingers) regions, while the lower limbs include trochanteric (hip), femoral (upper leg), knee, leg and foot. It may be helpful to remember that some regions are correlated with the names of underlying structures: the deltoid and pectoral regions are named for the muscles in that area, while sternal and trochanteric regions refer to skeletal structures underneath.

BODY ORGANIZATION

Posterior regions of the body 4

II

m

KAPLAN) MEDICAL

MEW 4. Posterior regions of the body

a. Head

b. Neck (cervical)

c. Scapular (shoulder blade)

d. Brachial (arm)

e. Vertebral

f. Olecranon (elbow)

g. Lumbar

h. Antebrachial (forearm)

I. Gluteal

j. Femoral (thigh)

k. Popliteal

I. Surat (calf)

m. Calcaneal

From the posterior aspect, one can see areas not visible from the anterior view, such as scapular (shoulder blade), vertebral, lumbar (lower back) and gluteal (buttocks) regions in the trunk. The upper limbs include the olecranon or elbow region, while the lower limbs include popliteal (back of knee), sural (calf) and calcaneal (heel) regions. The olecranon and calcaneus are bone structures in their respective regions.

5 Body cavities

Dorsal body cavity:

a

b

111411114-7—T— d e

f

g

Abdominopelvic cavity:

Thoracic cavity:

V

KAPLAN) MEDICAL

•

5. Body cavities

a. Cranial cavity 1. Pleural cavity

b. Spinal canal g. Posterior mediastinum

c. Superior mediastinum h. Abdominal cavity

d. Anterior mediastinum i. Retroperitoneal space

e. Middle mediastinum j. Pelvic cavity (pericardial cavity)

Body cavities are surrounded by the exterior surface and skeletal elements within the head and trunk region, providing protection and a place for soft tissues and organs to grow and function. The dorsal body cavity is found in the head and along the midline of the posterior aspect of the trunk; it encloses the brain and spinal cord. The larger ventral body cavity is divided into the thoracic and abdominopelvic cavities by the diaphragm. The thoracic cavity includes the right and left pleural cavities containing the lungs, and the mediastinum, bounded by the pleural cavities laterally, the sternum anteriorly, and the vertebral column posteriorly. The trachea, esophagus and the major blood vessels pass through the mediastinum, which may be divided into several compartments—the anterior, posterior, superior and middle or pericardial cavity; the latter encloses the heart. The abdominopelvic cavity includes the abdominal cavity, which extends from the inferior surface of the diaphragm to the superior edge of the pelvic bones, and the pelvic cavity with the urinary bladder, reproductive organs and the terminal portion of the digestive tract.

• 4

BODY ORGANIZATION

Skeletal and visceral structures of the head and neck 6

KAPLAN) MEDICAL

6- A

.......

■

I

6. Skeletal and visceral structures of the head and neck

a. External occipital protuberance

b. Styloid process c. C4 - Fourth cervical vertebra d. Carotid tubercle of C6 e. Vertebra prominens f. First rib g. Esophagus h. Acromion process I. Coracoid process

j. Scapula k. Sternum I. Clavicle m. Thyroid gland n. Thyroid cartilage o. Hyoid bone p. Mandible q. Nasal bone r. Zygomatic bone s. Frontal bone

An overview of head and neck structures shows skeletal elements surrounding and protecting the brain and spinal cord. The cranium extends from the frontal bone anteriorly to the occipital bone posteriorly. A small bump on its inferior surface is the external occipital protuberance. The facial bones include the nasal and zygomatic bones, which help to form the bridge of the nose and the orbit of the eye, respectively. The mandible is the lower jaw. In the neck region, the esophagus is part of the digestive tract and, anterior to it, the trachea is part of the respiratory system. At the junction of the head and neck is the small hyoid bone, held in place by ligaments from the styloid process of the temporal bone (forming the lateral surfaces of the cranium); the hyoid supports the larynx which is protected by the thyroid cartilage. Inferior to the larynx is the thyroid gland, which secretes the hormone thyroxin. The neck joins the trunk at the pectoral girdle—including the clavicle and scapula—that supports the upper limbs. The clavicles also provide a connection with the axial skeleton where they articulate with the sternum. The coracoid and acromion processes of the scapula provide an attachment point for numerous muscles and ligaments.

a ,

b

Thoracic, abdominal and pelvic viscera, anterior view 7

KAPLAN) MEDICAL

7. Thoracic, abdominal and pelvic viscera, anterior view

a. Thyroid cartilage

b. Thyroid gland

c. Clavicle

d. Arch of aorta (behind sternum)

e. Third rib

f. Outline of heart

g. Left lung

h. Spleen

1. Stomach

j. Transverse colon

k. Small intestine

1. Outline of descending colon (behind small intestine)

m. Sigmoid colon

n. Outline of rectum

o. Urinary bladder

p. Ascending colon

q. Gall bladder

r. Liver

s. Right lung

t. Superior vena cava (behind sternum)

u. Hyoid bone

Organs of several body systems share the space within the cavities of the trunk. The superior part of these cavities is protected by the ribs, sternum and vertebral column of the axial skeleton, while the inferior portion is supported by the pelvic girdle. The thoracic cavity contains the lungs which surround the pericardial cavity containing the heart. Venous blood enters the heart through the vena cava and is pumped from the heart to the body through the aorta; this critical area is well protected behind the sternum. In the abdominal cavity, the digestive tract includes the stomach, small intestine, colon (ascending, transverse, descending and sigmoid), and rectum. Accessory glands of the digestive system include the liver, gall bladder and pancreas. The spleen is an organ of the circulatory, lymphatic and immune systems. The urinary bladder is located in the lower part of the abdominal cavity.

Thoracic, abdominal and pelvic viscera, posterior view 8

KAPLAN) MEDICAL ■

8. Thoracic, abdominal and pelvic viscera, posterior view

a. Atlas b. Pharynx

c. Thyroid gland

d. Trachea

e. Right lung

1. Right adrenal gland

g. Liver

h. Pancreas

I. Right kidney

j. Small intestine

k. Ascending colon

L Iliac crest

m. Pelvic girdle

n. Seminal vesicle

o. Sacrum

p. Descending colon

q. Left ureter

r. Left kidney

s. Spleen

t. Outline of pancreas

u. Diaphragm

v. Esophagus

w. Left lung

x. First thoracic vertebra

The posterior view clearly shows the position of the vertebral column, extending from the atlas that articulates with the cranium to the fused vertebrae that form the sacrum, which articulates with the pelvic girdle. The wide pharynx at the rear of the nose and mouth divides into two passageways—the posterior esophagus leading to the stomach and the anterior trachea or windpipe. The rear of the thoracic cavity is filled with the lungs. The diaphragm is a thin sheet of muscle that marks the boundary between the thoracic and abdominal cavities, and functions in breathing. Accessory digestive organs include a large liver and the deep, mostly hidden pancreas, while the small intestine and parts of the colon are also visible from this view. The excretory system includes the dorsal, paired kidneys that form urine, and the ureters that carry the urine to the bladder. Superior to the kidney lie paired adrenal glands, part of the endocrine system. The only reproductive structures in view are the seminal vesicles, found only in the male.

4

BODY ORGANIZATION

Thoracic, abdominal and pelvic viscera, 9 right lateral view

KAPLAN) MEDICAL

9. Thoracic, abdominal and pelvic viscera, right lateral view a. Horizontal fissure of lung j. Rectum

b. Gall bladder k. Ureter

c. Stomach L Right kidney

d. Transverse colon m. Li vertebra

e. Ascending colon n. Liver

1. Small intestine o. Oblique fissure of lung

g. Ovary p. Right lung

h. Urinary bladder q. C7 vertebra

I. Uterus

The right lung is divided into three lobes by the horizontal and oblique fissures. In the abdominal cavity, the digestive tract occupies the largest part of the space, including the stomach, small intestine, colon and rectum. The small intestine terminates on the right side, leading into the ascending colon and then to the transverse colon. The gall bladder, an accessory organ of the digestive system, is found on the posterior surface of the right lobe of the liver. The kidneys lie near the posterior wall of the abdominal cavity, with the right kidney being positioned slightly inferior compared with the left. The kidneys and ascending colon are retroperitoneal, while the small intestine and transverse colon are peritoneal. Ureters lead from the kidneys down to the inferior and anterior position of the bladder. The female reproductive structures, the ovary and uterus may be found between the bones that form the pelvis.

1111111=1

Thoracic, abdominal and pelvic viscera, 10 left lateral view

KAPLAN) MEDICAL

10. Thoracic, abdominal and pelvic viscera, left lateral view

a. C7 vertebra b. Oblique fissure of lung

c. Left dome of diaphragm d. Spleen e. L1 vertebra

1. Prostate gland j. Urinary bladder k. Descending colon 1. Small intestine m. Transverse colon

1. Left kidney n. Stomach

g. Ureter o. Liver

h. Rectum p. Left lung

The left lung is divided into two lobes by an oblique fissure. The diaphragm is located between the thoracic and abdominal cavities, and forms a dome shape when relaxed. Usually lying left and ventral to the lobes of the liver is the stomach, which then leads to the small intestine, colon, and rectum. On the right side, the transverse colon leads to the descending colon, before undigested materials empty into the rectum for compaction and elimination. Posterior to the stomach is the left kidney, with the ureter funneling urine to the bladder. Although many male reproductive structures are located outside the abdominopelvic cavity, the prostate gland is found near the bladder.

...... KAPLAN) MEDICAL

INTEGUMENTARY SYSTEM

Layers of the skin and associated structures 11

Mr 11. Layers of the skin

a. Sweat gland b. Meissner's corpuscle c. Hair

d. Epidermis

e. Dermis

1. Hypodermis

and associated structures

g. Papillary layer h. Reticular layer I. Hair follicle

j. Sebaceous gland k. Pacinian corpuscle I. Arrector pili muscle

The integumentary system includes the largest organ of the body—the skin. It functions to protect underlying body parts from water loss, chemical insult, and physical harm. Specialized structures detect pressure, pain or temperature stimuli; Meissner's corpuscles sense light touch while Pacinian corpuscles sense deep pressure. Sebaceous glands secrete lipids that inhibit bacteria and lubricate the hair shaft. Sweat glands secrete water, waste products and electrolytes, in part to cool the skin and reduce body temperature. A cross-section of human skin reveals layers of the skin; the interface between the layers is often indistinct as one layer merges into the next. The epidermis consists of stratified squamous epithelium that provides mechanical protection against invasion by microorganisms. The dermis has a superficial papillary layer of areolar tissue, with capillaries and sensory neurons that supply the epidermis; and a deeper, thicker reticular layer with dense, irregular connective tissue and networks of blood vessels, lymph vessels, and nerve fibers. Many of the accessory organs such as hair follicles and sweat glands are embedded in the reticular layer. The subcutaneous layer, or hypodermis, consists of areolar and adipose tissue; distribution of body fat in this layer varies between the sexes or at different times in life (such as the presence of "baby fat").

INTEGUMENTARY SYSTEM

Epidermis

—a

:,...... , ...44...,

— b

. . "

, .1 .. ... • 0 0 •• • ° "••

.. . 0•'• 0 •..

- • • ao 0 0 =

0 0 ,.., 0 0 • 0 , NZ • a

0, . . 0 a —d ...

" - - 0 a

a 0 0 ••• •

..., "

a 6 a O • • 0 ®

90 • 9

• .' 0.0, •• .•

. 0 0 .

or •

- o 0 s 0 • .0

— C

•• •

•

•

KAPLAN) MEDICAL

12. Epidermis Epidermis

a. Stratum corneum b. Stratum lucidum c. Stratum granulosum

d. Stratum spinosum e. Stratum basale 1. Melanocyte

Skin epidermis includes numerous layers or "strata" of cells. The innermost "basal" layer of epidermal cells includes cells capable of cell division—one daughter cell remains in the stratum basale while the other is pushed into the adjacent "spiny" layer, the stratum spinosum, where a few cells may continue to divide. As additional cells are produced and pushed into the stratum spinosum, existing cells are pushed toward the surface. In the stratum granulosum, cells begin to produce keratin and the granular keratohyalin. The thick skin of palms and soles also includes the stratum lucidum, which is extensively keratinized; it is missing in the so-called "thin skin" found over the remainder of the body. The outer layer, the stratum corneum, consists of dead, "cornified" cells that contain keratin and are relatively water resistant. Melanocytes are special cells found in the basal layers; these cells make the pigment melanin and transfer it to keratinocytes. (These pigmented cells are found in deep layers in light-skinned individuals but in more superficial layers in those with darker skin.) Melanin is protective against ultraviolet•induced damage.

INTEGUMENTARY SYSTEM

1(.APLA) MEDICAL

13. Hair

a. Hair follicle b. Hair root c. Hair shaft d. Matrix

e. Papilla 1. Sebaceous gland g. Arrector pili muscle h. Bulb

While humans possess less hair than most mammals, hair follicles are found on most areas of the skin except for parts of the hands and feet. Only 2-3% of a human's hairs are found on the head. The hair shaft is composed of dead, keratinized cells arranged in several layers. The hair follicle arises from the hair bulb, usually found in the subcutaneous or hypodermis layer; the follicle continues through the dermis, and the hair shaft that is produced protrudes through the epidermis. At the base of the follicle is the connective tissue papilla, containing capillaries and nerves. Around the papilla is the matrix, consisting of epithelial cells that divide to form the cells of the hair root. As cells continue to be produced in the matrix, they are pushed upward in the follicle, become keratinized, die, and harden to form the hair shaft. Associated arrector pill muscles control the angle of hair position, pulling the hair toward a vertical position when stimulated; the muscles also squeeze on sebaceous glands and push lipid secretions into the follicle to lubricate the hair shaft.

INTEGUMENTARY SYSTEM

Fingernail

\_ b

KAPLAN) MEDICAL ..,...

14. Fingernail

a. Free edge b. Hyponychium c. Nail plate d. Distal phalanx

e. Nail bed 1. Eponychium g. Germinal matrix h. Nail root

Nails form on the dorsal surfaces of the tips of the fingers and toes. They protect the exposed ends of the fingers and toes when they are subjected to mechanical stress, for example, when grasping or running. At the base of the nail, an epidermal fold called the eponychium allows the nail root to remain sequestered below the skin surface, near the distal phalanx bone. New nail is produced at the germinal matrix, near the nail root. The nail plate covers an area of epithelium called the nail bed that is continuous with the germinal matrix on its proximal side; the nail bed contains blood vessels and nerves. As the nail plate is produced, it streams along the surface of the nail bed and is attached to it through grooves on the underside of the nail plate. The free edge of the nail covers the hyponychium, an area where the nail bed meets the adjoining epidermis. The nail itself consists of hard, tightly packed, dehydrated cells that are packed with keratin. The keratin protein forms an extremely strong and hard protein matrix that is not readily soluble in water.

Skeleton, anterior view 15

KAPLAN) MEDICAL

SKELETAL SYSTEM

15. Skeleton, anterior view a. Frontal bone b. Maxilla c. Mandible d. Clavicle e. Humerus 1. Costal cartilage g. Thoracic vertebra h. Ulna i. Hip bone (os coxae) j. Sacrum k. Phalanges I. Patella m. Fibula

n. Metatarsals o. Phalanges p. Tarsals q. Tibia r. Femur s. Metacarpals t. Carpals u. Lumbar vertebra v. Radius w. Ribs x. Sternum y. Cervical vertebra z. Zygomatic bone

The axial skeleton has 8o bones, including the skull and associated bones, the rib cage, and the vertebral column. Looking at the axial skeleton from the anterior aspect beginning with the head, one sees the frontal bone which is part of the cranium, the maxilla, zygomatic and mandible which are all facial bones, the cervical, thoracic, and lumbar vertebrae, the sacrum and coccyx, as well as the ribs which are connected to the sternum through the costal cartilage. The cranium and vertebral column protect the brain and spinal cord; the rib cage protects internal organs and facilitates breathing. The appendicular skeleton consists of 126 bones, including the pelvic and pectoral girdles and the limbs. Parts of the appendicular skeleton observed anteriorly include the clavicle of the pectoral girdle, the humerus, ulna, radius, carpals, metacarpals, and phalanges of the upper limbs, the hip bone of the pelvic girdle, the femur, patella, tibia, fibula, tarsals, metatarsals and phalanges of the lower limb. The pectoral and pelvic girdles connect the limbs to the axial skeleton; it is the appendicular skeleton that allows one to move about in the environment.

Skeleton, posterior view

KAPLAN) MEDICAL

SKELETAL SYSTEM

16. Skeleton, posterior view

a. Parietal bone n. Metatarsals b. Mastoid process o. Fibula c. Scapula p. Metacarpals d. Humerus q. Hip bone (os coxae) e. Ulna r. Lumbar vertebra 1. Radius s. Ribs g. Carpals t. Thoracic vertebra h. Sacrum u. Acromion I. Phalanges v. Cervical vertebra j. Femur w. External occipital k. Tibia protuberance

I. Tarsal x. Occipital bone

m. Calcaneus

Bones of the cranium include the parietal and occipital; the external occipital protuberance is the bump obvious at the mid•sagittal point on the inferior margin of the cranium. The spinal cord is protected by vertebrae, including the cervical (7), thoracic (12) and lumbar (5), as well as the fused vertebrae that make up the sacrum. The upper limbs articulate with the scapula of the pectoral girdle; the acromion is a large process of the scapula that articulates with the clavicle, which in turn, attaches to the sternum. Upper limb bones include the humerus, ulna and radius; wrist bones are carpals; hand bones are metacarpals; and finger bones are phalanges. The pelvic girdle supports the weight of the torso and the hip bone articulates with the lower limbs, which include the femur, tibia and fibula; ankle bones are tarsals, the largest of which is the calcaneus or heel bone; foot bones are metatarsals; and toe bones are phalanges.

J

SKELETAL SYSTEM

17

KAPLAN) MEDICAL -.....

Anterior view of the skull

1

17. Anterior view of the skull

a. Orbit

b. Frontal bone

c. Temporal bone

d. Sphenoid bone

e. Nasal bone

f. Zygomatic bone

g. Nasal septum

h. Maxilla

I. Mandible

The skull is composed of eight cranial bones and fourteen facial bones. Looking at the anterior surface, the facial bones include two nasal, two zygomatic, two maxillae, and one mandible. The maxillae and mandible form the upper and lower jaws. The maxillae and zygomatic form the inferior surfaces of the orbits, or eye sockets, while the superior rim of the orbit consists of the frontal bone and the back of the orbit is formed by the sphenoid, both cranial bones. The nasal bones and maxillae form the bridge and lateral rim of the nasal opening. The nasal cavity is subdivided by the nasal septum, formed from deeper facial bones including the vomer and one of the deep cranial bones—the ethmoid. Cranial bones observed from this aspect include the frontal, which forms the forehead, and two temporal bones on the lateral surfaces.

---1 SKELETAL SYSTEM

Skull, lateral view

18

KAPLAN) MEDICAL .....

18. Skull, lateral view

a. Coronal suture n. Zygomatic bone

b. Parietal bone o. Nasal bone

c. Zygomatic process p. Lacrimal bone d. Temporal bone q. Sphenoid bone e. Squamous suture r. Frontal bone 1. Lambdoid suture s. Coronoid process

g. External occipital t. Mandibular foramen protuberance u. Mandibular notch

h. Occipital bone v. Mandibular condyle I. Mastoid process w. Ramus of mandible j. External acoustic meatus x. Angle of mandible k. Styloid process y. Body of mandible L Mandible z. Mental foramen m. Maxilla

Observed from the lateral aspect, one can identify the large braincase formed by the cranial bones, including a single frontal, two parietal, two temporal, one occipital, one sphenoid and one ethmoid which is not seen in this view. The temporal bone has several processes that articulate with bones or provide attachment sites for muscles and ligaments, and the external acoustic meatus or external ear. The temporal bone articulates with the parietal bone at an immovable joint, the squamous suture. The mandible forms the lower jaw; it articulates with the temporal bone at the mandibular condyle. The strong temporalis muscle that closes the jaw attaches at the coronoid process. Openings in the mandible include the mental foramen for nerves and the mandibular foramen for blood vessels and nerves. Other facial bones visible from this aspect include the maxilla, zygomatic, nasal and lacrimal bones.

1 SKELETAL SYSTEM

Skull, superior view 19

KAPLA) MEDICAL ....

19. Skull, superior view

a. Frontal bone d. Sagittal suture

b. Corona( suture e. Lambdoid suture

c. Parietal bones f. Occipital bone

Sutures are immovable joints between cranial bones where the bones are held together securely by dense fibrous tissue. The two parietal bones articulate at the sagittal suture. The frontal bone articulates with the two parietal bones at the corona! suture. The parietal bones meet the occipital bone at the lambdoid suture. However, at birth, an infant's skull is still growing and the bones do not completely meet; they are connected only by relatively large areas of fibrous tissue called fontanels. Most of the fontanels disappear within a few months after birth, although the largest may take a year or two before it closes completely.

I SKELETAL SYSTEM

External surface of the base of the skull 20

KAPLA) MEDICAL ■

A

20. External surface of the base of the skull

a. Palatine process of maxilla b. Vomer c. Greater wing of

sphenoid bone d. Medial pterygoid plate

of sphenoid bone e. Mandibular fossa f. Carotid canal g. Jugular foramen h. Foramen magnum i. External occipital

protuberance

j. Occipital condyle k. Mastoid process 1. Styloid process m. Foramen lacerum n. Foramen ovate o. Zygomatic arch p. Lateral plate of

sphenoid bone q. Palatine bone r. Incisive fossa

The hard palate is formed by the palatine process of the maxillae anteriorly and the palatine bones posteriorly; the incisive fossa forms a passageway for nerves and arteries. The vomer forms the bony part of the nasal septum. The pterygoid plates are extensions of the sphenoid bone that form attachment sites for muscles that move the lower jaw. The foramen magnum is the large hole in the occipital bone through which the spinal cord passes; on either side, the occipital condyles articulate with the first vertebra of the neck. Between the foramen magnum and the external occipital protuberance, a bony crest marks attachment sites for ligaments stabilizing the vertebrae of the neck. The mastoid process of the temporal bone provides an attachment site for muscles rotating the head; muscles attached to the styloid process control the hyoid, the pharynx and the tongue. Holes for passage of blood vessels and nerves include the carotid canal and foramen lacerum in the temporal bone, the foramen ovate in the sphenoid bone, and the jugular foramen formed at the junction of the temporal and occipital bones. A depression in the temporal bone, the mandibular fossa, articulates with the mandible.

SKELETAL SYSTEM

Median sagittal section of the skull

21

KA 1:,1_...)_AN MEDICAL

21. Median sagittal section of the skull

a. Frontal bone b. Frontal sinus c. Crista galli d. Nasal bone e. Cribriform plate of

the ethmoid bone 1. Perpendicular plate of

the ethmoid bone g. Vomer h. Maxilla 1. Palatine bone

j. Mandible k. Coronal suture I Squamosal suture m. Parietal bone n. Temporal bone o. Sella turcica p. Occipital bone q. Internal acoustic meatus r. Sphenoid bone s. Sphenoid sinus

A sagittal section of the skull shows the inner surface of the braincase, including the frontal, parietal, occipital, sphenoid, ethmoid and temporal bones. The inner ear opens through the temporal bone at the internal acoustic meatus. The sella turcica is a saddle-like portion of the sphenoid that encloses the pituitary gland which projects from the surface of the brain. Facial bones include the nasal, vomer, maxilla, palatine, and mandible. Several bones have hollow spaces known as sinuses to make the bones lighter and to provide a source of mucus; cross sections of these bones reveal the frontal sinus and the sphenoid sinus. The nasal cavity lies superior to the hard palate; its roof is formed by the cribriform plate of the ethmoid while the perpendicular plate of the ethmoid forms part of the nasal septum. The crista gain is a ridge of the ethmoid that projects superiorly from the cribriform plate.

1 SKELETAL SYSTEM

Right temporal and sphenoid bones 22

Right temporal bone, lateral view

Sphenoid bone, superior view

Ki... 31......)AN MEDICAL

.4

22. Right temporal and sphenoid bones Temporal bone:

a. Squamous part

b. Zygomatic process

c. Mandibular fossa

d. External acoustic meatus

e. Styloid process

f. Mastoid process

Sphenoid bone:

g. Hypophysial fossa (sella turcica, pituitary fossa)

h. Optic canal

i. Lesser wing

I. Superior orbital fissure

k. Greater wing

I Foramen spinosum

m. Pterygoid hamulus

n. Dorsum sellae

o. Foramen ovate

P. Foramen rotundum

q• Anterior clinoid process

The large, flat surface of the temporal bone is the squamous region. The mandibular fossa is a depression that articulates with the mandible. The zygomatic process articulates with the zygomatic bone to form the cheekbone, while the mastoid process is an attachment site for muscles, and the styloid process is an attachment site for muscles and ligaments supporting the hyoid bone. The external acoustic meatus provides the opening for the auditory canal. The sphenoid bone is a butterfly-shaped bone that articulates with both cranial and facial bones and provides cross-bracing that serves to strengthen the skull. The central region or body is composed of the dorsum setae and the sella turcica, which contains a depression where the pituitary gland is located, the hypophysial fossa. The lesser wing of the sphenoid is located anterior to the sella turcica; it is penetrated by the optic canal carrying the optic nerve from the rear of the orbit toward the brain. The greater wing is lateral to the body. The superior orbital fissure, foramen spinosum, foramen ovate, and foramen rotundum are passages that carry blood vessels and nerves to the face, jaws or eye region.

■ SKELETAL SYSTEM

Hyoid bone 23

KAPLAN) MEDICAL

_J

23. Hyoid bone

a. Lesser horn b. Greater horn c. Body

The small hyoid bone is located at the base of the tongue and immediately superior to the larynx. It is crucial to human speech as it braces the tongue and larynx to allow a wide range of movements. The body of the hyoid is an attachment site for muscles of the pharynx, larynx and tongue. The greater horns support the larynx and provide attachment sites for muscles moving the tongue. The lesser horns are suspended from the styloid processes of the temporal bones via ligaments.

SKELETAL SYSTEM

Vertebral column, lateral view

24

KAPLAN) MEDICAL S....

J

24. Vertebral column, lateral view

a. Cervical vertebrae C. Lumbar vertebrae

(cervical curvature) (lumbar curvature) b. Thoracic vertebrae d. Sacrum (pelvic curvature)

(thoracic curvature) e. Coccyx

The vertebral column is the part of the axial skeleton that surrounds and protects the spinal cord, while bearing the weight of the head, neck and trunk. The vertebral column is not straight, as can be seen in this lateral view; its curves accommodate the thoracic and abdominopelvic viscera as well as balance the weight of the trunk and head over the lower limbs. Regions of the vertebral column and their corresponding curves include 7 cervical vertebrae (the cervical curve is concave on the posterior surface), 12 thoracic vertebrae (the thoracic curve is convex on the posterior surface), 5 lumbar vertebrae (the lumbar curve is concave), a sacrum (pelvic or sacral curve is convex), and a coccyx.

SKELETAL SYSTEM

1

Posterior view of the vertebrae

25

KAPLA.5) MEDICAL

A

25. Posterior view of the vertebrae a. Cervical vertebrae

d. Sacrum b. Thoracic vertebrae

e. Coccyx c. Lumbar vertebrae

The adult human vertebral column consists of 26 bones-7 cervical vertebrae (C1•C7, including the atlas[Ci] and axis[C2D form the neck, 12 thoracic vertebrae (Ti-T12) support the upper back and articulate with ribs, 5 lumbar vertebrae (11-15) support the lower back, a sacrum consisting of 5 fused vertebrae articulates with the pelvis, and a coccyx resulting from the fusion of the final 4-6 vertebrae. Generally, one spinal nerve emerges at each vertebra; however, although there are only 7 cervical vertebrae, there are 8 cervical nerves. Each individual vertebra consists of a vertebral body or centrum that transfers weight to the next lower vertebra, a vertebral arch forming the posterior margin of the vertebral canal, and variable types of processes that either provide attachment points for muscles or articulate with ribs. The 5 sacral vertebrae begin fusing after puberty and are usually completely fused by age 25-30. The coccyx is not completely fused until late in adulthood.

Atlas (Ci) and axis (C2), superior view

26

a Atlas

i

e

Atlas and Axis

SKELETAL SYSTEM

KAPLAN) MEDICAL

26. Atlas (Ci) and axis (C2), superior view

a. Posterior tubercle j. Posterior arch

b. Vertebral foramen k. Facet for odontoid

c. Lateral mass process of axis

d. Transverse foramen I. Bifid spinous process

e. Superior articular m. Body of axis

process (facet) n. Odontoid process (dens)

f. Anterior tubercle o. Arch of axis (lamina)

g. Anterior arch p. Axis

h. Transverse process q. Atlas

I. Groove for vertebral artery

The first cervical vertebra is called the atlas; its superior articular processes have facets that articulate with the occipital condyles of the skull in a type of joint that permits forward•backward motion of the head. The body of the second cervical vertebra, the axis, has a prominent odontoid process that extends superiorly and articulates with a facet on the atlas, providing a pivot point to allow rotational movement of the head. The facet of the superior articular process of the axis articulates with a similar flat surface on an inferior articular process of the atlas. Like other individual vertebrae, the axis has a prominent dorsal spinous process, which is notched as it is in cervical vertebrae 3-6 and is referred to as bind; the atlas has a smaller dorsal process known as the posterior tubercle. Laterally, a transverse process provides attachment sites for muscles, while the transverse foramen allows passage of vertebral arteries and veins.

Superior view

SKELETAL SYSTEM

Cervical vertebra, superior and lateral views 27

I(APLA) MEDICAL

27. Cervical vertebra, superior and lateral views

a. Bifid spinous process 1. Transverse process b. Vertebral foramen g. Body

c. Lamina of vertebral arch h. Uncus of vertebral body

d. Pedicle of vertebral arch I. Transverse foramen

e. Superior articular process j. Inferior articular process

Cervical vertebrae have a relatively large vertebral foramen, since the spinal cord still includes most of the axons that exit the brain, and the vertebral body only needs to support the weight of the head. The vertebral foramen is bounded by the body anteriorly, the pedicles laterally, and the laminae posteriorly. Where the lamina meet is a posteriorly projecting protrusion called the spinous process, which is notched, or bifid, for C2-C6. Articular processes lie at the junction between the pedicles and laminae; each has a relatively flat surface, the facet, which articulates with the articular process of the neighboring vertebra. The superior articular process articulates with the vertebra above, and the inferior articular process articulates with the vertebra below. The uncus is a ridge of bone around the superior edge of the body in cervical vertebrae, increasing the stability of the joint with the vertebra above it. Laterally, transverse processes provide attachment sites for neck muscles; a hole, the transverse foramen, allows passage of vertebral arteries and veins.

Superior view

h

Lateral view

SKELETAL SYSTEM

Thoracic vertebra, superior and lateral views 28

KAPLAN) MEDICAL

28. Thoracic vertebra, superior and lateral views a. Spinous process b. Vertebral foramen

c. Transverse process

d. Superior articular process

e. Superior costal facet

1. Body

g. Pedicle

h. Lamina

I. Costal facet of transverse process

j. Inferior articular process

k. Inferior costal facet

The twelve thoracic vertebrae each have a larger body and smaller vertebral foramen than found in the cervical vertebrae. A long, slender dorsal spinous process projects inferiorly. The superior and inferior articular processes articulate with adjacent vertebrae. The thoracic vertebrae articulate with ribs; the superior and inferior costal facets arise at the junction between the vertebral body and pedicle for T2-T8, while a single costal facet is found for Ti and T9-712. Two facets are needed for T248 because each pair of ribs lies between two adjacent vertebrae, articulating with the inferior costal facet of the upper vertebra and the superior costal facet of the vertebra inferior to it. For Ti and T9412, a single pair of ribs articulates with a single vertebra. The ribs also articulate with the costal facet of the transverse process in vertebrae Ti-Tto. The multiple articulations help the ribs to be mobile enough for the change in volume of the rib cage during breathing.

Lumbar vertebra, superior and lateral views

29

Superior view r--/a

f

Lateral view

e

I(APLA) MEDICAL ,••■

SKELETAL SYSTEM

29. Lumbar vertebra, superior and lateral views

•

a. b. c. d.

Spinous process Vertebral foramen Superior articular process Transverse process

e. Body of vertebra 1. Pedicie g. Lamina (vertebral arch) h. Inferior articular process

The five lumbar vertebrae are the most massive of the vertebral column since they support the most weight, and each has a thick, oval body. Lumbar vertebrae have the smallest vertebral foramina because many of the axons from the brain have already branched out from the spinal cord into the torso or upper limbs. The spinous process is short, sturdy and projects dorsally; lower back muscles are attached here that adjust the lumbar curve of the vertebral column. The superior articular process faces medially while the inferior articular process faces laterally. Transverse processes are slender and project dorsolaterally.

r SKELETAL SYSTEM

Sacrum and coccyx, anterior view 30

a

KAPLAN) MEDICAL ...■

30. Sacrum and coccyx, anterior view

a. Sacral pro montory d. Transverse lines b. Superior a rticular process e. Anterior sacral foramina c. Lateral m ass (ala) f. Coccyx

Five sacral vertebrae fuse to form the sacrum, while 3.5 coccygeal vertebrae fuse to form the coccyx. These vertebrae begin fusing after puberty; the sacrum is usually completely fused by the mid•twenties, while the coccyx is not completely fused until late in adulthood. The coccyx is a vestigial remnant of the tail of evolutionary ancestors, but in humans, has no vertebral foramen and does not surround a part of the spinal cord. The regions of the sacrum include the sacral promontory that articulates with the last lumbar vertebra (L5), the two broad lateral masses (ala) on either side, and the central sacral body, corresponding to the fused vertebral bodies; the transverse lines mark the position of the intervertebral discs between the bodies of the fused vertebrae. The anterior sacral foramina provide passageways for sacral nerves as well as arteries.

SKELETAL SYSTEM

Sacrum and coccyx, posterior view

31

KAPLAN) MEDICAL .,..

J

31. Sacrum and coccyx, posterior view

a. Superior articular process

d. Median sacral crest

b. Auricular surface

e. Posterior sacral foramina

c. Lateral sacral crest

1. Coccyx

The posterior surface of the sacrum is convex, allowing room within the pelvic region for internal organs and providing many surfaces for attachment of muscles and ligaments. Laterally, the auricular surfaces articulate with the pelvis at the iliac joints. The median sacral crest is a bumpy ridge produced from the fused spinal processes of the sacral vertebrae; deep to this ridge is the sacral canal which is the continuation of the vertebral canal. The lateral sacral crest represents the fused transverse processes of the sacral vertebrae. Between the two ridges are the posterior sacral foramina, passageways for sacral nerves as well as arteries. Sexual differences exist—in the female, the sacrum is shorter and wider than in the male, with most of the curvature in the lower half, but it is more evenly distributed in the male.

1 SKELETAL

SYSTEM

Intervertebral discs, lateral and midsagittal views 32

a

a

1

1(All MEDICAL

32. Intervertebral discs, lateral and midsagittal views

a. Intervertebral disc g. Supraspinous ligament b. Superior articular process h. Interspinous ligament c. Transverse process I. Ligamentum flavum d. Inferior articular process j. Posterior longitudinal e. Intervertebral foramen ligament

1. Anterior longitudinal ligament

A lateral view of the vertebral column shows that adjacent bodies of the vertebrae are cushioned by the intervertebral discs that permit some extension and flexion of the spine. Intervertebral discs are composed of fibrocartilage that resists compression but allows a little flexibility. The pedicles of adjacent vertebrae are separated by the Intervertebral foramina that allow the passage of nerves entering or exiting from the spinal cord that runs through the vertebral foramen within the vertebral arch formed in part by the pedicles. The lamina of adjacent vertebrae articulate through the facets on the superior and inferior articular processes, while the transverse processes project laterally. Ligaments connect and stabilize the vertebrae. Anterior and posterior longitudinal ligaments run along the bodies of the vertebrae, supraspinous and interspinous ligaments connect the dorsal spinous processes, and the ligamentum flexum connects the adjacent laminae.

SKELETAL SYSTEM

Sternum, anterior view 33

MEDICAL

33. Sternum, anterior view

a. Suprasternal notch b. Clavicular notch c. Manubrium d. Sternal angle

e. Costal notches 1. Body g. Xiphoid process

The sternum, part of the axial skeleton, functions to protect and support the internal organs of the thoracic cavity, and to form an attachment point for ribs. It has three main portions—the superior section is the triangular manubrium that articulates with the clavicles, the main body, and the small xiphoid process located inferior to the body. The superior edge of the manubrium has two points of attachment for the clavicles, located laterally on either side of the medial depression known as the suprastemal notch. At the point of attachment between the manubrium and body of the sternum is the sternal angle, a convenient marker located at the level of the second rib. The anterior ends of ribs 1-7 articulate with the sternum; the first rib articulates with the manubrium at sites inferior to the clavicular notches, and ribs 2.7 have cartilage connections to the body of the sternum at the costal notches. Ribs 8.10 are attached by cartilage to the cartilage connections of rib 7. The xiphoid process forms an attachment point for some muscles, including the diaphragm.

34 Rib and vertebra, articulated, superior view; rib, posterior view

SKELETAL SYSTEM

KAPLAN) MEDICAL

■

34. Rib and vertebra, articulated, superior view; rib, posterior view

a. Thoracic vertebra e. Angle of rib

b. Head of rib f. Costal groove

c. Neck of rib g. Sternal extremity

d. Tubercle of rib

The ribs function to protect the organs of the thoracic cavity and to provide a flexible cavity for breathing. The thoracic vertebrae articulate with the ribs; the head of the rib attaches at the costal facets near the body of the vertebrae while the tubercle of the rib is positioned at the costal facet of the transverse process. The shaft of the rib curves anteriorly at the angle of the rib. Along the inferior border of the internal surface of the rib lies a costal groove which marks the site where nerves and blood vessels pass. Cartilage connected to ribs 17 at the sternal extremity articulate with the sternum at the costal notches. Cartilage attached to ribs 8•io, in turn, attaches to the cartilage from rib 7.

SKELETAL SYSTEM

Rib cage, anterior view 35

KAPLA) MEDICAL

-1

•••■

4

35. Rib cage, anterior view a. 1st thoracic vertebra b. Clavicle c. Scapula d. Costal cartilage e. 12th thoracic vertebra

f. 1st lumbar vertebra g. 12th rib h. nth rib I. Sternum j. 1st rib

The rib cage consists of the sternum and the 12 pairs of ribs, which are attached posteriorly to the thoracic vertebrae. Ribs 1-7 articulate with the sternum through the costal cartilage; for ribs 8.io the costal cartilage articulates only indirectly with the sternum since it fuses to the cartilage of rib 7 for support. Ribs 11-12 do not attach to the sternum at all; they are connected with other skeletal elements only at the vertebral end. The articulation between the axial skeleton and the pectoral girdle occurs where the clavicle, or collarbone, attaches to the sternum at the manubrium; in turn, the clavicle articulates with the scapula or shoulder blade. The function of the rib cage is to protect the heart, lungs and other thoracic organs as well as to serve as an attachment point for muscles involved in movements of the pectoral girdle and upper limbs, adjustments to the position of the vertebral column, and most importantly, breathing.

SKELETAL SYSTEM

Pectoral girdle and upper limb, anterior view 36

KAPLA) MEDICAL

36. Pectoral girdle and upper limb, anterior view a. Clavicle

b. Acromion process

c. Coracoid process

d. Humerus

e. Radius

1. Sternum

g. Scapula

h. Ulna

i. Carpals

j. Metacarpals

k. Phalanges

The pectoral girdle is composed of four bones, two clavicles and two scapulae. The acromion and coracoid processes of the scapulae are points of attachment for numerous ligaments and muscles. The clavicle articulates with the sternum of the axial skeleton medially, and with the scapula laterally. The primary function of the pectoral girdle is to provide an anchor for movements of the arm. Each upper limb consists of a humerus in the (upper) arm, an ulna and a radius in the forearm, eight carpal bones in the wrist, five metacarpal bones in the hand, and u; phalanges or finger bones. At the shoulder, the humerus articulates with the scapula to produce a wide range of arm movements; at the elbow, the humerus articulates with the radius and ulna to flex the forearm, while articulation between the radius and ulna allows pronation of the forearm. The complex wrist joint provides for a wide range of movements while the finger joints allow flexion and extension of the fingers.

•

SKELETAL SYSTEM

Scapula, anterior and lateral views 37

e

d

f

Anterior view

b

Lateral view

MEDICAL

37. Scapula, anterior and lateral views

a. Acromion process

e. Subscapular fossa b. Superior border

1. Lateral border c. Coracoid process

g. Medial border d. Glenoid fossa

h. Inferior angle

Viewed from the anterior perspective, the scapula has an obvious large, triangular surface that is roughly concave, forming the subscapular fossa; its edges are, observed in a clockwise direction from this aspect, the superior border, medial border, inferior angle, and lateral border. Between the superior and lateral borders, the scapula articulates with the humerus at the shoulder joint. The glenoid fossa is the concave 'socket' within which the rounded head of the humerus rotates. Two processes also originate in this area and extend superiorly; the more anterior is the coracoid process which is an attachment point for ligaments and tendons; posterior to this is the larger acromion process, which articulates with the clavicle as well as being the attachment point for additional ligaments and tendons of the shoulder joint. The lateral view clearly shows that these two processes project from the thin plane of the scapula; the rounded nature of the glenoid fossa also becomes more obvious.

SKELETAL SYSTEM

Scapula, posterior view

38

KAPLAI9 MEDICAL

38. Scapula, posterior view

a. Acromion process b. Coracoid process c. Glenoid fossa d. Infraspinous fossa e. Lateral border

f. Inferior angle g. Medial border h. Supraspinous fossa I. Superior angle J. Spine

The basic triangular shape of the scapula is bound by the superior angle, the medial border, the inferior angle, and the lateral border. Muscles attached to these margins position the scapula; there is no direct articulation of the scapula with the vertebrae or rib cage. Located in the angle between the lateral and superior borders, the glenoid fossa articulates with the humerus of the arm. The posterior surface is marked by the prominent ridge called the scapular spine, which is continuous with the acromion process. The clavicle articulates with the acromion process at the medial surface of its anterior projection. The spine divides the posterior face of the scapula into a smaller supraspinous fossa and a larger infraspinous fossa; both are sites of attachment for numerous muscles of the shoulder and back.

Clavicle and related bones, superior view; clavicle, inferior view

Superior view

39. Clavicle and related bones, superior view; clavicle, inferior view

a. First thoracic vertebra (Ti)

e. Conoid tubercle

b. First rib

f. Sternal end of clavicle

c. Scapula

g. Sternum

d. Acromial end of clavicle

Looking down from above the head and shoulders reveals the superior aspect of the pectoral girdle including both the clavicle and scapula. The girdle is anchored to the axial skeleton by a single articulation anteriorly, and is held in position posteriorly by many small muscles attached to the scapula; this provides mobility but limited strength to the shoulders as they provide the anchor for arm motions. The S-shaped clavicle articulates medially with the manubrium of the sternum just above the first rib, and laterally with the acromial process of the scapula. The acromial end of the clavicle is broader than the sternal end; at the posterior margin of the inferior surface near the acromial end is the conoid tubercle which is an attachment point for the conoid ligament that also attaches to the coracoid process of the scapula.

40 Humerus, anterior and posterior views

Anterior view Posterior view

SKELETAL SYSTEM

KAPLA!:1) MEDICAL

J

40. Humerus, anterior and posterior views

a. Greater tubercle b. Lesser tubercle c. Intertubercular sulcus d. Head e. Anatomical neck 1. Surgical neck g. Deltoid tuberosity

h. Supracondylar ridges i. Lateral epicondyle j. Coronoid fossa k. Olecranon fossa 1. Medial epicondyle m. Capitulum n. Trochlea

The rounded head of the humerus moves within the cup-shaped glenoid fossa of the scapula. Adjacent to the head are two projections on the lateral surface of the humerus—the greater tubercle is the most lateral point of the body at shoulder level and the lesser tubercle lies on the anterior, medial surface and is separated from the greater tubercle by a shallow groove, the Intertubercular sulcus. Muscles attach to both tubercles while a large tendon passes along the length of the sulcus. The edge of the joint capsule is called the anatomical neck, while the narrower surgical neck marks the metaphysic of the growing bone. The deltoid muscle attaches to the shaft at the deltoid tuberosity. At the distal end of the humerus, the capitulum and the trochlea articulate with the radius and ulna, respectively. The radial, coronoid and olecranon fossae are depressions that accommodate the radial head, ulnar coronoid process and ulnar olecranon as they move. Laterally, the humerus widens out in the medial and lateral epicondyles; supracondylar ridges provide attachment sites for muscles.

SKELETAL SYSTEM

Ulna and radius, lateral and anterior views

a

41

b

d

e

g

k.

Ulna, lateral view Ulna and radius, anterior view

KAPLAN) MEDICAL

41. Ulna and radius, lateral and anterior views

a. Olecranon process

b. Trochlear notch

c. Coronoid process

d. Radial notch

e. Tuberosity of the ulna

f. Head of radius

g. Radial tuberosity

h. Interosseous margin

I. Ulnar notch

j. Styloid process of ulna

k. Head of ulna

I. Styloid process of radius

The bones of the forearm are the ulna and radius. The more medial and longer ulna articulates with the trochlea of the humerus at the trochlear notch. The superior edge of the trochlear notch is the olecranon process which fits into the olecranon fossa of the humerus when the forearm is extended, and the inferior edge of the trochlear notch is the coronoid process which fits into the coronoid fossa of the humerus when the forearm is flexed. Lateral to the coronoid process, the radial notch of the ulna articulates with the head of the radius. Distal to the radial head, the radial tuberosity forms an attachment site for muscles. A fibrous sheet called the interosseous membrane connects the radius and ulna along the interosseous margins, and serves as a site for muscle attachment. At their distal ends, the ulna and radius articulate with each other, and the radius articulates with bones of the wrist. The lateral surface of the ulnar head articulates with the ulnar notch of the radius. A stytoid process extends distally from each of the bones, providing many attachment sites for ligaments and muscles of the wrist.

1 SKELETAL SYSTEM

Hand, posterior (dorsal) view 42

KAPLAN) MEDICAL ......

4

42. Hand, posterior (dorsal) view

a. Phalanges g. Triquetrum b. Head of metacarpal

h. Lunate c. Shaft of metacarpal

I. Metacarpal d. Base of metacarpal

J. Trapezoid e. Hamate

k. Trapezium f. Capitate

L Scaphoid

Eight carpal bones make up the flexible wrist, articulating at individual joints that allow limited, gliding motion between the bone surfaces. The proximal row of carpals includes the scaphoid bone, lunate bone, triquetrum, and pisiform bone; the distal row consists of the trapezium, trapezoid bone, capitate bone, and the hamate bone. Articulating with the distal carpal bones are the five metacarpal bones, forming the hand. The metacarpals are identified by roman numerals; metacarpal I is most lateral, forming the base of the thumb, and articulates with the trapezium. The proximal base of each metacarpal articulates with the carpals. The metacarpal heads articulate distally with phalanges, or finger bones. The thumb has two phalanges; each of the other fingers has three, making a total of 14 phalanges on each hand. The joint between metacarpal I and the trapezium at the base of the thumb is a saddle joint, allowing more range of motion than found with the other metacarpals, and leading to the abilities associated with having an "opposable" thumb.

SKELETAL 1

SYSTEM

Hand, anterior (palmar) view 43

KAI......_21.).AN MEDICAL

43. Hand, anterior (paha° view

a. Phalanges f. Scaphoid

b. Metacarpal g. Lunate

c. Trapezoid h. Pisiform

d. Trapezium i. Hamate

e. Capitate

Since the anatomical position is defined with the palms of the hands facing forward, the thumb is more lateral while the fingers are more medial. Among the proximal carpal bones, the lateral scaphoid bone articulates with the styloid process of the radius; the lunate bone also articulates with the radius. The triquetrum articulates with the cartilaginous disc that separates the head of the ulna from the wrist; the small, anterior pea•shaped pisiform bone is seen primarily from the anterior view and only articulates with the triquetrum. Among the distal carpal bones, the lateral trapezium articulates with metacarpals I and II; the trapezoid bone articulates with metacarpal II; the capitate articulates with metacarpals II, Ill, and IV; and the hamate articulates with metacarpals IV and V. The distal head of each metacarpal articulates with the more proximal of the phalanges in the finger; the thumb has proximal and distal phalanges while each finger has proximal, medial and distal phalanges.

SKELETAL SYSTEM

44 Hip bone, lateral view

Adult hip bone

p

Hip bone of a child

KAPLAN) MEDICAL

•

44. Hip bone, lateral view

a. Iliac crest b. Posterior superior iliac spine c. Posterior inferior iliac spine d. Greater sciatic notch e. Ischia' spine f. Lesser sciatic notch g. Ischia' tuberosity h. Ischial ramus i. Acetabulum

I. k. I. m. n. o.

p. q.

Obturator foramen Inferior pubic ramus Superior pubic ramus Anterior inferior iliac spine Anterior superior iliac spine Ilium Ischium Pubis

The hip bone, or os coxae, is formed from the fusion of three bones—the ilium, ischium, and pubis. The fusion lines are visible in the child's hip bone image, showing how the three bones meet to form the acetabulum which is seen clearly in the lateral view and articulates with the head of the femur. Anterior to the acetabulum are the superior and inferior rami of the pubis; posterior to the acetabulum is the ischium, extending from the Ischia( spine on the superior edge to the ischial ramus which meets the inferior pubic ramus. The Ischia' tuberosity is the rounded protrusion that bears one's weight when seated. The space immediately inferior to the acetabulum is the obdurator foramen which is filled by a sheet of collagen fibers that provide sites for attachment of muscles. Superior to the acetabulum is the large broad ilium, which supports the weight of the internal organs of the trunk; muscles, tendons and ligaments attach at sites including the iliac crest and various iliac spines. The greater sciatic notch allows passage of the sciatic nerve to the lower limbs; blood vessels and nerves pass along the lesser sciatic notch.

SKELETAL SYSTEM

Pelvis, anterior view 45

(

KAPLAN) MEDICAL

45. Pelvis, anterior view

a. Iliac crest

b. Sacroiliac joint

c. Greater sciatic notch

d. Anterior superior iliac spine e. Anterior inferior iliac spine

1. Acetabulum

g. Obturator foramen

h. Symphysis pubis

I. False pelvis

j. True pelvis

The pelvis is formed from the two ossa coxae of the appendicular skeleton and the sacrum and coccyx of the axial skeleton. Because it supports the weight of the upper body and mediates the stresses of locomotion, the bones are larger and heavier than those of the pectoral girdle. The ilium of the ox coxae articulates with the sacrum at the sturdy sacroiliac joint. The iliac crest forms the superior, posterior edge of the pelvis, while the anterior superior iliac spines mark the lateral edges. The anterior and inferior limit of the pelvis is composed of the pubis bones, medial to the obdurator foramen; the pubis bones are connected by fibrocartilage at the symphysis pubis. The true pelvis (or lesser pelvis) is the cavity posterior to the pubic symphysis, anterior to the sacrum and coccyx, and bounded by the medial surfaces of the ilia near the greater sciatic notch. The false pelvis (or greater pelvis) is the larger, more superior cavity bounded laterally by the anterior superior iliac spines.

SKELETAL SYSTEM

Differences between male and female pelvis

46

KAPLAN) MEDICAL

46. Differences between male and female pelvis

a. Wing (ala) of ilium d. Subpubic angle, b. Subpubic angle, female (wider)

male (narrower) e. True pelvis, female c. True pelvis, male (wider, oval)

(narrower, heart-shaped)

Males and females show gender-related differences in the pelvis, due partly to the larger size and muscle mass of males, and partly to adaptations in females for childbearing. Generally, the female pelvis has lighter bones with smoother surfaces; it is broader and has less depth than the male pelvis. The broad surface of the ilium, known as the ala or wing, projects further laterally in females, but the iliac crest is not located as far superior from the level of the sacrum. The subpubic angle formed between the two pubis bones at the pubic symphysis is larger in females. The sacrum and coccyx are less curved in females at the inferior, anterior side, leading to a larger and more circular opening at the inferior side of the cavity known as the true pelvis. Overall, the true pelvis is wider and more oval in females to allow for childbirth, while it is narrower and somewhat heart-shaped in males.

SKELETAL SYSTEM

Lower limb, anterior view 47

11Apl.....)-AN MEDICAL

47. Lower limb, anterior view

a. Femur e. Tarsals

b. Patella

1. Metatarsals

c. Tibia g. Phalanges

d. Fibula

The lower limb must withstand the stresses of locomotion and bearing the body's weight; for this reason, the bones are more massive than the bones of the upper limbs. The lower limbs are supported by the pelvis. The bones of the lower limbs include the femur, which articulates proximally with the pelvis at the acetabulum of the hip bone and distally with the tibia and patella. Lateral to the tibia is the fibula, but only the tibia articulates with the tarsals, the ankle bones. At the ankle, the foot turns 9o° compared with the leg bones, to provide stability as the body's weight is transferred to the ground. The bones of the foot include the metatarsals and the phalanges, or toe bones.

•

SKELETAL SYSTEM

Femur and patella, anterior and posterior views 48

Anterior view Posterior view

KAPLArs) MEDICAL

48. Femur and patella, anterior and posterior views

a. Greater trochanter

b. Head of femur

c. Neck of femur

d. Intertrochanteric line

e. Intertrochanteric ridge

f. Lesser trochanter g. Linea aspera

h. Lateral epicondykle

I. Medial epicondyle

j. Lateral condyle

k. Medial condyle

L Base of patella

m. Apex of patella

The femur, or thigh bone, is the largest and strongest bone in the human body. The head of the femur articulates with the pelvis at the acetabulum; the head is joined to the shaft of the femur through the neck at an angle of about125°. The rim of the articular capsule is marked anteriorly by the Intertrochanteric line and posteriorly by the intertrochanteric ridge. Adjacent to the neck are the superior greater trochanter and the inferior lesser trochanter, both sites where large tendons attach. The Linea aspera is a ridge running along the posterior side of the femur where strong hip muscles attach. At the distal end, the femur widens out, forming the lateral and medial epicondyles. Inferior to the epicondyles are the lateral and medial condyles, the surfaces that articulate with the tibia at the knee. A deep groove, the intercondylar fossa, extends between the condyles on the posterior side. Between the condyles anteriorly, there is a smooth surface over which the patella can glide. The patella has an inferior apex connected to the tibia by a ligament; a broad, superior base; a smooth, convex anterior surface; and posterior facets for articulating with the condyles of the femur.

r Anterior view Posterior view

q

11 SKELETAL SYSTEM

Tibia and fibula, anterior and posterior views 49

KAPLAN) MEDICAL

49. Tibia and fibula, anterior and posterior views

a. Lateral tibial condyle k. Lateral surface of tibial shaft b. Intercondylar eminence I Posterior surface of tibia c. Medial tibial condyle m. Medial surface of tibial shaft

d. Apex of fibula n. Interosseous borders e. Head of fibula o. Malleolar groove 1. Tibial tuberosity p. Medial malleolus g. Soleal line q. Lateral malleolus h. Medial crest of fibula r. Inferior articular surface I. Anterior border of fibula of tibia

I. Anterior border (crest) of tibia

The tibia, or shinbone, articulates with the lateral and medial condyles of the femur at the lateral and medial tibial condyles. Between the condyles, the intercondylar eminence provides attachment for cruciate ligaments. Anteriorly, the tibial tuberosity is a site of attachment for the patellar ligament. The distal end of the tibia has an Inferior articular surface that articulates with a proximal tarsal bone. Adjacent to this is the medial malleolus, a large process that lends stability to the ankle joint; the malleolar groove is a tendon passageway. The fibula, or calf bone, is a long, slender bone. The head of the fibula articulates with the lateral tibial condyle, while the inferior end of the tibia also articulates with a flat region on the side of the fibula. The lateral malleolus is a fibular process that continues inferiorly beyond the articulation with the tibia, providing lateral support for the ankle joint. Along the shaft of both bones, prominent crests, borders, and lines mark the attachment sites for muscles or the interosseous membrane that helps stabilize the positions of the two bones and provides additional muscle attachment sites.

SKELETAL SYSTEM

Bones of the foot, dorsal view 50

!CAPLAN) MEDICAL

50. Bones of the foot, dorsal view

1. Phalanges g. First (medial) cuneiform 2. Metatarsals h. Second (intermediate) 3. Tarsals cuneiform

a. Distal phalanges I. Third (lateral) cuneiform

b. Middle phalanges j. Cuboid

c. Proximal phalanges k. Navicular

d. Head of metatarsal 1. Talus

e. Shaft of metatarsal m. Calcaneus

f. Base of metatarsal

The bones of the foot include seven tarsal or ankle bones, five metatarsal or foot bones, and 14 phalanges or toe bones. The toes each have distal, middle and proximal phalanges, with the exception of the most medial "great" toe, which only has two phalanges (like the thumb)—the distal and proximal. Each metatarsal has a head that articulates with the proximal phalanges, a shaft, and a base that articulates with the tarsals. The talus is a large tarsal that articulates with the tibia at a process that also articulates with the lateral malleolus of the fibula. The calcaneus or heel bone is the largest tarsal. The navicular bone is anterior to the talus and articulates with the medial, intermediate and lateral cuneiform bones, that in turn articulate with metatarsal bones I—III. Anterior to the calcaneous and lateral to the navicular and cuneiforms is the cuboid bone, which articulates with metatarsals IV and V.

1 SKELETAL SYSTEM

Bones of the foot, lateral view

51

KAPLAN) MEDICAL ....

•

51. Bones of the foot, lateral view

a. First (medial) cuneiform g. Middle phalanx b. Second (intermediate) h. Proximal phalanx

cuneiform I. Head of metatarsal c. Third (lateral) cuneiform j. Shaft of metatarsal d. Navicular k. Base of metatarsal e. Talus L Cuboid 1. Distal phalanx m. Calcaneus

The large tarsus called the talus articulates with the tibia to distribute the weight of the body evenly, both toward the distal end of the metatarsals and also toward the heel. Anteriorly, the talus articulates with the navicular bone, which in turn articulates with the medial, intermediate and lateral cuneiform bones. These tarsals then articulate with metatarsals I, II and III. Additionally, the talus articulates with the calcaneus or heel bone. Anteriorly, the calcaneus articulates with the cuboid bone, which then articulates with metatarsals IV and V. Ligaments and tendons attach to tarsals and metatarsals to maintain an arched position that lifts the medial bones so that blood vessels, nerves and muscles are not squeezed between the bones and the ground. The elasticity of the arch also helps to cushion the shocks that arise as the weight shifts during walking or running. The heads of the metatarsals articulate with the proximal phalanxes of each toe.

4

KAPLAN) MEDICAL

ARTICULATIONS

Gomphosis (peg suture) 52

52. Gomphosis (peg suture)

a. Tooth

b. Alveolar socket

c. Enamel

d. Dentin

e. Pulp

f. Gingiva

g. Alveolar ridge

h. Periodontal ligaments

A gomphosis is a fibrous synarthrotic (immovable) joint holding a tooth in its alveolar socket in the maxilla or mandible. The bulk of the tooth is

composed of dentin, a mineralized matrix secreted by cells found in the

pulp cavity. The exposed portion of the tooth is covered by a crystalline

calcium phosphate layer called enamel—the hardest substance in the

human body. The root of the tooth is bound in place by the periodontal ligament; it is composed of collagen fibers extending from the dentin

of the tooth to the bone surrounding the root of the tooth. A bony

alveolar ridge forms the deep socket or alveolus where the peg-like

root of the tooth is inserted. Superficial to the bone is the gingiva, mucosal tissue tightly bound to the bone surrounding the teeth; it

provides a smooth surface to reduce friction with food.

ARTICULATIONS

Suture 53

KAPLAN.) MEDICAL

53. Suture

a. Sagittal suture

A suture is a fibrous synarthrotic (immovable) joint located between

the bones of the skull, in order to form a protective case for the brain

and sensory organs of the head. Cranial sutures include the sagittat suture shown here, which connects the two parietal bones and extends

between the anterior coronal suture and the posterior lambdoid

suture. Further attachment between bones at the suture is provided

by collagen fibers that bind the bones in a firm but slightly flexible

manner. The bone edges at the sutures are interlocking in adults,

although they are slightly separated and are only connected by fibrous

connective tissue during development to allow both more flexibility

of the skull during birth and room for growth as the brain increases in

size during the early postnatal period.

ARTICULATIONS

Syndesmosis, posterior view 54

KAPLAN) MEDICAL

54. Syndesmosis, posterior view

a. Tibia e. Posterior tibiofibular

b. Fibula ligament

c. Interosseous membrane 1. Transverse tibiofibular

d. Interosseous ligament ligament

A syndesmosis is a fibrous amphiarthrotic (slightly moveable) joint

where the articulation between the bones is strengthened considerably

by a ligament or network of collagen fibers that connects them. The

syndesmosis between the tibia and fibula permits a small amount of

movement between them. The interosseous membrane is composed

of collagen fibers that connect the interosseous borders along most of

the length of the tibia and fibula; it is continuous with the interosseous

ligament, composed of fibers which connect the rough surfaces where

the tibia and fibula meet. The anterior, posterior and the deeper

transverse tibiofibular ligaments are strong bands of collagen that

extend from the distal end of the tibia to the lateral malleolus of the

fibula. The strength of the tibiofibular articulation is critical for the

strength of the ankle joint.

Synchondrosis 55

KAPLAN) MEDICAL ,...

ARTICULATIONS

55. Synchondrosis

a. Sternum: manubrium

b. First costal cartilage

c. First rib

A synchondrosis is a fibrous synarthrotic (immovable) joint where

the two articulating bones are joined by cartilage. While there are

many examples of synchondroses in the developing skeleton, such as

growth plates in the long bones that become completely ossified in the

adult, the sternocostal joint between the first rib and the manubrium of the sternum remains a synchondrosis throughout adult life. The

costal cartilage of rib i is hyaline cartilage that is continuous with the

rib laterally and with the sternum medially. For other ribs, the costal

cartilage is continuous with the rib laterally, but either fits into a

depression on the sternum (ribs 2-7), connects with the costal cartilage

on other ribs (ribs 8-so), or ends in the body wall (ribs 11-12).

Symphysis 56

1

ARTICULATIONS

a

c

KAPLAN) MEDICAL .......

56. Symphysis

a. Intervertebral disc

b. Lumbar vertebra

c. Sacrum

A symphysis is a cartilaginous amphiarthrotic (slightly moveable) joint

where a pad of fibrocartilage separates the two bones. Intervertebral discs are found between the bodies of adjacent cervical (except Ci

and C2), thoracic, and lumbar vertebrae, and between the fifth lumbar vertebra and the sacrum. The intervertebral disc includes a tough outer

layer called the annulus fibrosis composed of layers of collagen fibers

oriented at various angles and attached to the bone of the vertebrae,

and an inner layer called the nucleus pulposus that is more hydrated

and consists of a gel-like material that resists compression. Movement

of the vertebral column displaces the nucleus pulposus in the opposite

direction, permitting smooth, gliding motion while retaining the

appropriate alignment of the vertebrae. The force exerted on the discs

as the vertebrae support the weight of the body precludes the presence

of blood vessels in the disc cartilage; nutrients must diffuse in from

surrounding tissues.

ARTICULATIONS

Synovial joint, diagrammatic sagittal section 57

KAPLA) MEDICAL -.....

57. Synovial joint, diagrammatic sagittal section

a. Bone

d. Meniscus

b. Joint capsule e. Articular cartilage

c. Synovial cavity

(synovial fluid)

Synovial joints are diarthrotic (freely moveable) joints where the

bone ends are enclosed within a joint capsule, that is lined by an

articular membrane. Within the synovial cavity, lubricating synovial

fluid is secreted by the areolar tissue of the synovial membrane.

The articulating surfaces of the bones are covered by a thin layer

of articular cartilage which provides a smooth surface that, when

lubricated by synovial fluid, reduces friction and allows ready

movement of the joint. In some synovial joints such as the knee, a

fibrocartilage pad, the meniscus, further separates the opposing bones

of the joint, or adapts the cavity shape to the specific shapes of the

bones of the joint. In addition to its role in lubrication, synovial fluid

functions in distributing nutrients to cartilage cells and absorbing the

shock of pressure changes during movement.

Tendon sheath 58

ARTICULATIONS

Anterior view

b

c

—d CC)

e

f

Cross -section view

KAPLAtO MEDICAL

f.

g.

58. Tendon sheath

a. Distal phalanx

b. Tendon insertion, flexor

digitorum profundus muscle

c. Tendon, flexor digitorum

profundus muscle

d. Middle phalanx

e. Fibrous digital sheath,

cruciate part

Proximal phalanx

Fibrous digital sheath,

annular part

h. synovial sheath

i. Tendon, flexor digitorum

superficialis muscle

A tendon sheath is a tubular pocket lined with synovial sheath and

filled with synovial fluid, that may surround tendons where they run

along a bony surface. The synovial fluid reduces friction and acts as

a shock absorber. Tendon sheaths in the fingers surround the long

tendons of the flexor digitorum profundus and the flexor digitorum superficialis that insert upon and flex the distal and middle phalanges,

respectively; the origins of these muscles are near the elbow. As its

name implies, the flexor digitorum superficialis is closer to the surface

as it crosses the palm but, since it inserts on the middle phalanx, the

fibers split, allowing the flexor digitorum profundus to pass from

deeper to more superficial, on its way to the distal phalanx. The tendon

sheath is thicker along the shaft of the phalanges, and thinner and

more flexible at the interphalangeal joints. Thickenings of the sheath

capsule are termed annular where the fibers are parallel and go

around the sheath, and cruciate where the fibers cross over each other.

The arrangement of these fibers ensures that the sheath will not be

pinched during flexion of the fingers.

Bursa 59

ARTICULATIONS

Sagittal section view

Lateral view

KAPLA) MEDICAL

59. Bursa

a. Calcaneus

b. Calcaneal (Achilles) tendon

c. Calcaneal bursa

Bursae are small pockets within connective tissue; they contain

synovial fluid, reduce friction, and act as shock absorbers. In the foot, a

bursa cushions the interface between the calcaneus and the calcaneal (Achilles) tendon. The calcaneal (Achilles) tendon is the largest tendon

of the body; it connects the gastrocnemius, soleus and plantaris

muscles of the calf of the leg to their insertion on the calcaneus. The

calcaneal bursa cushions the space just above the insertion point

and between the tendon and bone; any injury or condition that puts

extra strain on the tendon can cause inflammation of the bursa and

consequent discomfort.

r- 1 ARTICULATIONS

Gliding joint 60

KAPLAN) MEDICAL ■■

60. Gliding joint

a. Superior articular process

b. Vertebrae

c. Inferior articular process

A gliding joint is a synovial joint where the two opposing surfaces

glide past one another. The movement is usually slight, and rotation

is prevented by the shape of the capsule and/or the arrangement of

ligaments. Articulations between the superior and inferior articular

processes of adjacent vertebrae are gliding joints. The articulating

surfaces of these processes are covered with cartilage. When the back

is flexed or rotated, small movements occur at these joints but not

between the bodies of the vertebrae. As one moves the torso to the

right or left, the superior articular process glides smoothly along the

lateral surface of the inferior articular process of the adjacent vertebra

to the superior side. The process on the left moves in an opposite

direction to that on the right. Infraspinous and supraspinous ligaments

prevent rotation, while the anterior and posterior longitudinal

ligaments hold the vertebral bodies stable relative to one another. This

also prevents the occurrence of larger movements that could injure the

spinal cord.

!CAPLAN) MEDICAL

ARTICULATIONS

Hinge joint 61

b

61. Hinge joint

a. Humerus

b. Ulna

A hinge joint is a synovial joint in which movement occurs in only one

plane, usually to flex or extend one body part against another. The

humeroulnar joint of the elbow is a hinge joint; it includes articulation

between the trochlea of the humerus and the trochlear notch of the

ulna as well as the articulation of the capitulum of the humerus with

the head of the radius. The brachialis muscle attached to the ulna and

the biceps brachii muscle attached to the radius both flex the lower

arm against the humerus. Muscles attached to the ulnar olecranon

extend or straighten the forearm. The elbow joint is very stable

because the humerus and ulna interlock, the articular capsule is very

thick, and a series of strong ligaments reinforce the joint.

KAPLAN) MEDICAL

--1

ARTICULATIONS

Rotating joint 62

62. Rotating joint

a. Ulna

b. Radius

A rotating joint is a synovial joint that rotates one bone in relation to

another. At the articulation between the proximal ends of the ulna and

radius, movement of the bones is limited to the rotation of the radial

shaft; this allows the distal end of the radius to roll across the anterior

surface of the ulna. Pronation refers to this movement of the hand

from the anatomical position with the palm facing front to the opposite

orientation with palm facing back; supination is the opposite motion.

Similarly, movement of the hand from the palm up position to the

opposite orientation with the palm facing down is also pronation; the

opposite motion is also supination.

KAPLAN) MEDICAL

ARTICULATIONS

Ball and socket joint 63

b

63. Ball and socket joint

a. Ilium

b. Femur

A ball and socket joint is a synovial joint where the rounded head of

one bone moves within a cup-shaped depression in the other. This

permits a wide range of motion, including both angular and rotational

movements, at this type of joint. In the hip joint, the "ball" is the

rounded head of the femur, which is offset about 125° from the shaft of

the femur. The head of the femur rests within the acetabulum, which is

the depression located at the junction between the ilium, ischium and

pubis bones. The joint capsule extends from the lateral and inferior

surfaces of the pelvis and joins the femur at the intertrochanteric line

and intertrochanteric crest; thus the entire head and neck of the femur

are enclosed within the capsule. The hip joint is extremely strong and

stable because of the extent of the socket, the strong articular capsule,

strong supporting ligaments, and the bulk of the surrounding muscles.

ARTICULATIONS

Condyloid joint

64

b C

KAPLAJ) MEDICAL

64. Condyloid joint

a. Radius

c. Lunate

b. Scaphoid

d. Triquetrum

A condyloid joint is a synovial joint in which an oval or ellipsoidal

articular face of one bone rests within a slight depression on the

opposing surface. This permits movement at the joint to occur in

either of two planes. At the wrist, the articular surface at the distal

end of the radius is a broad shallow depression. The articular surfaces

of the scaphoid and lunate bones are more convex and shaped to

fit the depression in the radius. This allows not only for the flexion

or extension of the hand at the wrist, but also for moving the hand

toward the body (adduction) or away from the body (abduction) when

considering the anatomical position of the hand. Movement at the wrist

also involves the ulna and the triquetrum bone, which do not articulate

with each other, but with a fibrocartilage pad between them. The wrist

is stabilized laterally and medially by the styloid processes of the

radius and ulna, respectively.

65. Saddle joint

a. Trapezium

b. First metacarpal

A saddle joint is a synovial joint where opposing articular faces are

convex along one axis and concave along the other. This allows angular

motion in a variety of directions, but prevents rotation. A saddle joint

exists in the carpometacarpal joint at the base of the thumb, at the

articulation between the trapezium and metacarpal. The range of

movements allowed at this joint include flexion and extension in the

plane of the palm, abduction and adduction in a plane at a right angle

to the palm, circumduction and opposition. It is the latter motion that

is important in the concept of the "opposable thumb," the evolution of

which is thought to have allowed humans to develop fine motor skills

and tool making capability.

ARTICULATIONS

Temporomandibular joint, sagittai section 66

I.M•1 MEDICAL

66. Temporomandibular joint, sagittal section

a. Zygomatic process of

c. Articular disc

temporal bone

d. Articular capsule

b. Articular surface, mandibular e. Head of mandible fossa of temporal bone

f. Mandible

The temporomandibular joint is a synovial joint with the unusual

characteristic of having an articular disk dividing the articular capsule

into two parts. The lower joint compartment is formed between

the head of the mandible and the articular disk; movements are

rotational—opening and closing the jaw. As the jaw closes, the coronoid

process of the mandible slides into a cavity medial to the zygomatic

process of the temporal bone. The upper joint compartment is formed

between the mandibular fossa of the temporal bone and the articular

disk; movements here are translational—moving the jaw forwards and

backwards or side-to-side. The great mobility of the mandible enables

flexibility while chewing or talking, but also results in a joint that can

be easily dislocated by forceful forward or lateral displacement of the

mandible.

ARTICULATIONS

Shoulder joint, frontal section

67

KAPL,1) MEDICAL

67. Shoulder joint, frontal section

a. Acromion

b. Articular cartilage

c. Glenoid labrum

d. Spine of scapula

e. Glenoid fossa

f. Scapula

g. Articular capsule

h. Humerus

i. Synovial sheath

j. Tendon, biceps brachii

muscle (long head)

The shoulder joint (glenohumoral joint) is the synovial joint with the

greatest range of motion in the human body. The rounded head of

the humerus articulates with the scapula at the cup-shaped glenoid

fossa, which is deepened by a lip-like projection of cartilage called

the glenoid labrum. The head of the humerus is covered with a thin,

smooth layer of articular cartilage to minimize friction. The articular

capsule is relatively loose to permit an extensive range of motion; it

extends from the scapula to the anatomical neck of the humerus. The

tendon of the long head of the biceps brachii muscle attaches within

the glenohumoral articular capsule; the tendon is protected by a

synovial sheath to minimize friction.

68

Isl MEDICAL

ARTICULATIONS

Shoulder ligaments, anterior view

68. Shoulder ligaments, anterior view

a. Acromion

b. Acromioclavicular ligament

c. Coracoacromial ligament

d. Coracoclavicular ligment,

trapezoid ligament

e. Coracoclavicular ligament,

conoid ligament

f. Clavicle

g. Coracohumeral ligament

h. Transverse humeral ligament

i. Humerus

j. Articular capsule

k. Coracoid process of scapula

L Scapula

The shoulder joint is partly stabilized by the bones of the pectoral

girdle—particularly where the acromion and coracoid process of the

scapula extend laterally, superior to the head of the humerus. Another

measure of stability for the shoulder comes from ligaments. The

acromioclavicular, coracoacromial and coracoclavicular ligaments

connect the two processes of the scapula with the clavicle. The

coracohumoral ligament arises on the coracoid process and passes

across the joint to the greater tubercle of the humerus. The transverse

humoral ligament passes between the greater and lesser tubercles

of the humerus, forming a canal along the intertubercular groove

for the passage of the tendon of the biceps brachii. But by far, the

majority of the stability of the shoulder joint comes from the muscles

that move the humerus—especially the muscles collectively known as

the "rotator cuff", including the supraspinatus, the infraspinatus, the

subscapularis, and the teres minor.

■

ARTICULATIONS

Elbow joint, sagittal section 69

KAPLAN) MEDICAL -....

69. Elbow joint, sagittal section

a. Triceps muscle

b. Body of humerus

c. Brachialis muscle

d. Biceps brachii muscle

e. Trochlea of humerus

f. Joint cavity

g. Ulna

h. Ulnar artery

The strongest part of the complex elbow joint can be seen in a

sagittal section through the humeroulnar joint when the forearm

is extended. This hinge joint is capable of flexing or extending the

forearm. The trochlea of the humerus fits into the trochlear notch of

the ulna. Muscles that flex the forearm include the brachialis that

inserts on the coronoid process of the ulna, and to a lesser extent,

the biceps brachii that inserts on the radius. Extension of the forearm

is accomplished by contraction of the triceps muscle which inserts on

the olecranon of the ulna.

KAPLAN) MEDICAL

ARTICULATIONS

Elbow ligaments, anterior view •

70

70. Elbow ligaments, anterior view

a. Humerus h. Interosseous membrae

b. Medial epicondyle i. Radius

c. Ulnar collateral ligament j. Radial tuberosity

d. Trochlea of humerus k. Radial annular ligament

e. Ulnar tuberosity I. Radial collateral ligament

f. Oblique cord m. Capitulum of humerus

g. Ulna n. Lateral epicondyle

The elbow joint is very stable for several reasons: the humerus and

ulna interlock, the articular capsule is very thick, and several strong

ligaments reinforce the joint. The ulnar collateral ligament extends

from the medial epicondyle of the humerus anteriorly to the coronoid

processes of the ulna and posteriorly to the olecranon. The annular

ligament binds the head of the radius with the radial notch of the ulna.

The radial collateral ligament extends from the lateral epicondyle

of the humerus to the annular ligament. Although the radioulnar

articulation allows rotational movement of the radius around the ulna,

the interosseous membrane allows only limited movement between

the two bones. The fibers of the oblique cord pass obliquely between

the bones just inferior to the ulnar and radial tuberosities.

71 Hip joint, frontal section

ARTICULATIONS

KAPLAN.) MEDICAL

71. Hip joint, frontal section

a. Coxal bone

d. Zona orbicularis of capsule

b. Articular cartilage

e. Articular capsule

c. Acetabular labrum

f. Femur

The hip joint is a sturdy synovial joint (ball and socket joint) between

the globular head of the femur and the cup-like acetabulum of the

coxal bone. A thin layer of articular cartilage covers both bone surfaces

to reduce friction. A fibrocartilage lip called the acetabular labrum

extends the edge of the acetabulum to increase its depth; it is located

slightly beyond the widest diameter of the femoral head to hold it

firmly in place. The articular capsule is strong and dense; it completely

encloses the head and neck of the femur, and extends beyond the

edge of the acetabulum. The capsule includes longitudinal bands of

fibers that stretch between the hip bone and the femur to strengthen

the joint; the zona orbicularis of the capsule includes deep circular

fibers that form a collar to hold the head of the femur tightly in the

socket. The joint permits a range of movements: flexion and extension,

adduction and abduction, circumduction and rotation.

ARTICULATIONS

Pelvic ligaments, posterior view 72

KAPLA) MEDICAL

72. Pelvic ligaments, posterior view

a. Iliac crest h. Femur

b. Posterior superior iliac spine i. Sacrospinous ligament

c. Iliolumbar ligament j. Superficial dorsal

d. Fifth lumbar vertebra sacrococcygeal ligament

e. Supraspinous ligament k. Sacrotuberous ligament

f. Short dorsal sacroiliac I. Articular capsule of the

ligaments hip joint

g. Long dorsal sacroiliac

ligament

Strong ligaments are necessary to stabilize the pelvis. The

supraspinous ligament that runs along the edges of the vertebral

dorsal spinous processes continues along the median sacral crest. In

addition, the iliolumbar ligament connects the fifth lumbar vertebra

both to the sacrum and the iliac crest. The sacroiliac joint is stabilized

by the horizontal short dorsal sacroiliac ligament between the sacrum

and the tuberosity of the ilium and by the oblique long dorsal sacroiliac

ligament connecting the sacrum to the posterior superior iliac spine.

The sacrotuberous ligament is connected at one end to the posterior

inferior iliac spine, the lower part of the sacrum, and the coccyx; the

other end attaches to the tuberosity and ramus of the ischium. Nearby,

the sacrospinous ligament extends from the sacrum and coccyx to the

spine of the ischium. The sacrococcygeal joint is stabilized by several

ligaments, including the superficial dorsal sacrococcygeal ligament. At the hip joint, strong ligaments reinforce the articular capsule that

encloses the head and much of the neck of the femur.

KAPLA) MEDICAL

ARTICULATIONS

I

Knee joint, anterior view 73

i

h

g

73. Knee joint, anterior view

a. Femur

b. Patella

c. Fibular collateral ligament

(lateral collateral ligament)

d. Lateral meniscus

e. Lateral condyle of tibia

f. Fibula

g. Tibia

h. Tibial collateral ligament

(medial collateral ligament)

i. Medial condyle of tibia

j. Medial meniscus

k. Patellar ligament

The articulation between the femur and tibia at the knee joint performs

a simple hinge function, primarily facilitating flexion and extension of

the lower leg. However, a small amount of medial and lateral rotation

(10° and 3o° respectively) is also possible. The medial and lateral

condyles of the femur articulate with the medial and lateral condyles

of the tibia; the medial and lateral menisci are fibrocartilage pads

that cushion and separate the bones within the joint. The patella is

held in place anterior to the distal portion of the femur by the patellar

ligament distally and the quadriceps muscle tendon proximally; it not

only protects the knee joint but also provides increased leverage for

the quadriceps muscle during knee extension. The patella resides at

its most superior location during full extension of the knee, and moves

as much as 7 cm inferiorly during flexion, until it is located between

the distal ends of the femoral condyles. To the side, the knee joint is

stabilized by the tibial (medial) collateral ligament and the fibular

(lateral) collateral ligament.

KAPLAN) MEDICAL

i

i

h

g

ARTICULATIONS

Bent knee joint, anterior view with patella removed 74 7

74. Bent knee joint, anterior view with patella removed

a. Femur

b. Articular cartilage

c. Anterior cruciate ligament

d. Lateral meniscus

e. Lateral condyle of tibia

1. Fibula

g. Tibia

h. Tibial collateral ligament

i. Medial condyle of tibia

j. Medial meniscus

k. Posterior cruciate ligament

With the knee bent and the patella removed, the interior of the synovial

joint is revealed. The articular cartilage protecting the articular

surface of the femur extends superiorly behind the position of the

patella, as part of the femoropatellar joint. The two femoral condyles

are separated from the two tibial condyles by the medial and lateral

menisci. These pads of fibrocartilage fill in the space between the

convex surface of the femoral condyle and the flatter surface of the

tibial condyle; they act as durable shock absorbers and contribute

to both stability and lubrication in the joint. Ligaments stabilize the

joint; the anterior cruciate ligament (ACL) extends between the lateral

condyle of the femur posteriorly and the intercondylar region of the

tibia anteriorly; the posterior cruciate ligament (PCL) connects the

posterior intercondylar region of the tibia with the medial condyle of

the femur anteriorly. The ACL resists forces pushing the tibia forward,

while the PCL resists forces pushing the tibia posteriorly relative to the

femur. Excessive abduction or adduction motion at the knee joint is

limited by the fibular (lateral) and tibial (medial) collateral ligaments.

ARTICULATIONS

Knee joint, sagittal section 75

h

KA PLAjet) MEDICAL

P 75. Knee joint, sagittal section

a. Femur f. Lateral meniscus, anterior

b. Lateral menniscus, horn

posterior horn g. Infrapatellar fat pad

c. Fibula h. Patella

d. Tibia i. Articular cartilage

e. Patellar ligament

A sagittal section through the lateral condyles of the femur and tibia

reveals the anterior-posterior relationships of the fully-extended

knee joint. Articular cartilage covers the convex articular surface

of the femur and the flatter articular surface of the tibia. Between

the two articular cartilages lies the C-shaped lateral meniscus, with

posterior and anterior horns positioned to fill the area between the

curving articular surfaces. Popliteal ligaments strengthen the back

of the synovial articular capsule. The fibula articulates with the tibial

epicondyle laterally and posteriorly; a collateral ligament extends

from the fibula to the lateral epicondyle of the femur to strengthen the

joint. Anteriorly, the patella moves along the femoral articular surface

when the quadriceps muscle flexes the knee; the articular cartilage

of the patella is one of the thickest due to the intense stresses of this

movement. The quadriceps muscle tendon attaches on the superior

surface and is continuous with the inferior patellar ligament. The

infrapatellar fat pad absorbs shocks and fills in the space below and

behind the patella.

"I

ARTICULATIONS

1

k

i

Ankle joint, posterior view 76

KAPLAN) MEDICAL .---...------

76. Ankle joint, posterior view

a. Fibula

b. Posterior tibiofibular

ligament

c. Transverse tibiofibular

ligament

d. Posterior talofibular

ligament

e. Posterior talocalcaneal

ligament

f. Calcaneofibular ligament

g. Calcaneal (Achilles) tendon

h. Calcaneus

i. Medial talocalcaneal

ligament

I. Talus

k. Deltoid ligament,

tibiocalcaneal part

I. Deltoid ligament, tibiotalar

part

m. Tibia

The posterior view of the ankle joint shows several ligaments that

stabilize the articulations between the leg and ankle bones. The

largest tendon in the human body is the calcaneal tendon (also known

as the Achilles tendon) that connects three lower leg muscles—the

gastrocnemius, the soleus, and the plantaris—with their insertion on

the calcaneus, the largest of the tarsal bones. Above the ankle, the

distal articulation of the tibia and fibula are stabilized by the posterior and transverse tibiofibular ligaments. Laterally, the ankle joint is

stabilized by connections between the lateral malleolus of the fibula

and the tarsal bones, including the talofibular and calcaneofibular

ligaments. On the medial side, the ankle is stabilized by ligaments

connecting the medial malleolus of the tibia with tarsal bones such as

the calcaneus and the talus, including the tibiocalcaneal and tibiotalar parts of the deltoid ligament. Articulations between the tarsal bones

are also stabilized by ligaments, such as the medial and posterior

talocalcaneal ligaments connecting the talus and calcaneus.

■

c

d

e

ARTICULATIONS

Ankle joint, frontal section 77

KAPLAN) MEDICAL

77. Ankle joint, frontal section

a. Tibia

b. Articular cartilage

c. Medial malleolus of tibia

d. Deltoid ligament, posterior

tibiotalar part

e. Deltoid ligament,

tibiocalcaneal part

f. Calcaneus

g. Calcaneofibular ligament

h. Lateral malleolus of fibula

i. Talus

j. Tibiofibular syndesmosis

k. Fibula

A frontal section through the talus shows its articulations with the tibia,

fibula, and calcaneus. The talus rests on the calcaneus and supports

the tibia; the ankle is stabilized on either side by the lateral malleolus

of the fibula and the medial malleolus of the tibia. The articular sufaces

of all these bones are covered with articular cartilage. On the medial

side, the deltoid ligament attaches to the medial malleolus of the tibia

and parts of it connect to the tarsal bones in four places, including the

posterior tibiotalar part (to the talus) and the tibiocalcaneal part (to

the calcaneus). Laterally, the fibula is connected to the calcaneus by

the calcanealfibular ligament. Further stability of the ankle is provided

by the sturdy connection between the tibia and fibula along much of

their shafts, the tibiofibular syndesmosis.

Superficial muscles of the body, anterior view

78. Superficial muscles of the body, anterior view

a. Frontalis

b. Orbicularis oris

c. Sternocleidomastoid

d. Deltoid

e. Biceps brachii

1. Brachioradialis

g. Palmaris longus

h. Iliopsoas

I. Pectineus

j. Quadriceps femoris

k. Peroneus longus

I. Tibialis anterior

m. Extensor digitorum longus

n. Orbicularis oculi

o. Trapezius

p. Pectoralis major

q. Serratus anterior

r. Brachialis

s. External oblique

t. Rectus abdominus

u. Tensor fasciae latae

v. Adductor longus

w. Sartorius

x. Gracilis y. Gastrocnemius

z. Soleus

Contraction of muscle tissue initiates virtually every movement made by the human body. When you blink your eyes, you are using the orbicularis ocull to close the eyelids; when you wrinkle your brow, you contract the frontalis muscle; when you play the trumpet, you use a sphincter muscle around the mouth called the orbicularis oris. The shoulders and arms are moved by a series of muscles attached to the pectoral girdle and the bones of the arm, such as the deltoid, pectoralis major, biceps brachii, and brachialis. Movement of the lower limbs is used to propel the individual from one place to another; this involves muscles attached to the pelvic girdle and the leg bones, such as the quadriceps lemon's, sartorius, gracilis, and gastrocnemius. Muscles in the body wall of the trunk that constrict to rotate the torso or aid in respiration and defecation include the rectus abdominus and external oblique.

Superficial muscles of the body, posterior view 79

KAPLA) MEDICAL ---

79. Superficial muscles of the body, posterior view

a. Sternocleidomastoid m. Soleus

b. Trapezius n. Semitendinosus

c. Teres Major o. Semimembranosus

d. Brachioradialis p. Iliotibial tract

e. Extensor carpi radialis longus q. Gluteus maximus

f. Flexor carpi ulnaris r. Gluteus medius

g. Extensor carpi ulnaris s. Extensor digitorum

h. Gracilis t. Extensor carpi radialis brevis

I. Adductor magnus u. External abdominal oblique

j. Biceps femoris v. Latissimus dorsi

k. Gastrocnemius w. Triceps

L Calcaneal tendon x. Deltoid

More than 600 muscles carry out the actions of moving body parts; in many cases, their names are descriptive regarding the location, origin, insertion, action, shape, etc. Thus, the two trapezius muscles together form a trapezoid shape between the neck, shoulders, and thoracic vertebrae; they act to shrug the shoulders and to pull the shoulder blades toward the vertebrae. The flexor carpi ulnaris and extensor carpi ulnaris are two muscles that act to flex or extend the wrist (carpus); they originate on the ulna. The triceps muscle is named because it has three heads that originate on either the scapula or the humerus; the muscle has a single tendon that inserts on the olecranon of the ulna so that it acts to extend the forearm. The gluteal muscles in the butt are named for their size—the gluteus maximus is larger than the gluteus medius or the deeper gluteus minimus.

Muscle forms: fusiform and flat sheet

80

a

b

c

d

e

KAPLAN) MEDICAL ■

80. Muscle forms: fusiform and flat sheet

Fusiform: Broad, flat sheet: a. Basic fusiform, Palmaris e. Latissimus dorsi

longus

b. Bicipital, Biceps femoris

c. Tricipital, Triceps surae (gastrocnemius and soleus)

d. Quadriceps femoris

Fusiform muscles are wide in the middle and taper at both ends. The patmaris longus is a slender, fusiform muscle that originates on the humerus and ends in a long tendon that inserts on the palmar fascia. A bicipital muscle has two heads or origins, as the biceps femoris with the long head originating on the ischium and the short head on the femur; the muscle inserts at the knee and both heads act to flex the knee. The triceps surae is a tricipital muscle with three heads; this composite muscle consists of the gastrocnemius with two heads originating on the femur and the soleus which originates on the tibia; the triceps surae inserts on the calcaneus and acts in plantar flexion of the foot. The quadriceps femoris is a quadricipital muscle with four heads originating on the ilium and femur; the muscle inserts on the patella and extends the knee. Other muscles occur in broad, flat sheets, such as the latissimus dorsi which is a triangular, flat muscle that originates along the thoracic and lumbar vertebrae as well as the sacrum and ilium; it inserts on the humerus and acts to extend, adduct and rotate the shoulder.

Muscle forms: pennate, circular, and multicaudal 81

a b c

d e

KAPLAN) MEDICAL ■

81. Muscle forms: pennate, circular, and multicaudal

Pennate:

a. Unipennate, semimembranosus

b. Bipennate, tibialis anterior

c. Multipennate, deltoid

Circular:

d. External sphincter ani, deep portion

Multicaudal:

e. Flexor digitorum profundus

In pennate muscles, the contracting fibers attach to the tendon at an oblique angle; they provide more stability and force, but the tendon is not moved as far as when the fibers are parallel to the tendon. All the muscle fibers are on the same side of the tendon in unipennate muscles, such as the semimembranosus muscle which extends between the ischium and the tibia. Bipennate muscles are more common and have muscle fibers on both sides of the tendon, including the tibialis anterior which is a shin muscle that flexes the foot. In multipennate muscles, the fibers attach on both sides of the tendon, and the tendon branches within the muscle; an example is the deltoid muscle that forms the rounded shape of the shoulder. Circular, or sphincter, muscles are arranged concentrically around an opening; a good example is the deep portion of the external sphincter ani muscle which closes off the anal canal at its orifice. Multicaudal muscles attach at multiple sites; the flexor digitorum profundus is a single muscle that inserts on the phalanges of the four fingers to flex them.

MUSCULAR SYSTEM

Muscle forms: cylindrical, triangular, 82

quadrilateral, biventral, multiventral

a

b

c

d

e

KAPLAN) MEDICAL

82. Muscle forms: cylindrical, triangular, quadrilateral, biventral, multiventral

a. Cylindrical, teres major d. Biventral, digastric

b. Triangular, deltoid e. Multiventral, rectus

c. Quadrilateral, pronator abdominis

quadratus

Named from the Latin word for round or cylindrical, the teres major muscle extends between the scapula and humerus; it adducts and rotates the arm. The triangular deltoid muscle covers the shoulder joint, extending from the clavicle and scapula to the humerus; different parts of the muscle act to flex, extend or rotate the humerus. The pronator quadratus muscle is a square, or quadrilateral, muscle that extends between the ulna and radius at their distal end; it acts to pronate the forearm. The digastric muscle consists of two bellies with different origins that unite in a single tendon that inserts on the hyoid bone; the longer, posterior belly originates on the mastoid process of the temporal bone, while the anterior belly arises on the mandible. The rectus abdominis muscle has multiple insertions; it arises on the pubis bone and three portions of the muscle insert on the fifth, sixth and seventh ribs.

Muscles of facial expression, anterior view

83. Muscles of facial expression, anterior view

a. Frontalis h. Levator anguli oris

b. Procerus I. Orbicularis oris

c. Orbicularis oculi j. Risorius

d. Levator labii superioris k. Depressor anguli oris alaeque nasi L Platysma

e. Levator labii superioris m. Depressor labii inferioris f. Zygomaticus minor n. Mentalis g. Zygomaticus major

Facial expressions result from muscular contractions that move the skin in particular facial regions. The frontalis muscle raises the eyebrows and wrinkles the brow. The procerus muscle wrinkles the skin at the top of the nose and flares the nostrils. The orbicularis oculi muscle closes the eye. The upper lip can be made to snarl by the levator [Ail superioris alaeque nasi muscle or to be raised by the levator [Ail superioris muscle. The muscles known as the zygomaticus minor and major, and levator anguli oris, draw the corners of the mouth superiorly and are used in smiling. The orbicularis oris is a sphincter muscle around the mouth that aids in pursing the lips. The risorius muscle draws the corner of the mouth laterally in a grimace and the depressor anguli oris muscle draws the corner of the mouth downwards in a frown. The depressor labii inferioris muscle pulls the lower lip down, while the mentalis muscle is involved in wrinkling the chin. The platysma draws the corners of the mouth down in expression of fright as well as drawing the skin of the neck upward when the teeth are clenched.

J

Muscles of facial expression, lateral view 84

KAPLAN) MEDICAL

84. Muscles of facial expression, lateral view

a. Frontalis part, occipitofrontalis

b. Orbicularis oculi

c. Procerus

d. Nasalis

e. Levator labii superioris alaeque nasi

1. Levator labii superioris

g. Orbicularis oris

h. Depressor labii inferioris

i. Depressor anguli oris

j. Risorius

k. Platysma

1. Zygomaticus major

m. Zygomaticus minor

n. Zygomatic arch

Muscles controlling facial expression often originate on bones and insert on the skin of the face. The frontalis portion of the

occipitofrontalis muscle covers the forehead from above the hairline to the eyebrows. The orbicularis oculi muscle arises on the frontal bone and circles the eye to the temple and the cheek. The procerus muscle extends from the nasal bone to the skin of the medial forehead, while the nasalis muscle extends from the maxilla to the nasal bone and compresses the nasal cartilage. The levator labii superioris alaeque nasi extends from the maxilla to the upper lip

and the levator labii superioris muscle arises on the margin of the orbit and inserts on the upper lip. The orbicularis oris is a sphincter muscle whose fibers arise on the maxilla and mandible, and insert

on the skin around the lips. The depressor labii inferioris and the depressor anguli oris muscles arise on the mandible and insert on

the lower lip or corner of the mouth, respectively. The risorius muscle pulls the corner of the mouth laterally. The platysma is a broad, flat muscle that covers the neck between the clavicle and the mandible. The zygomaticus minor and major muscles arise along the zygomatic arch and insert on the upper lip or corner of the mouth, respectively.

Superficial muscles of mastication, lateral view 85

KAPLAN) MEDICAL -...

85. Superficial muscles of mastication, lateral view

a. Temporalis

d. Buccinator b. Zygomatic arch

e. Mandible c. Orbicularis oris

1. Masseter

Mastication, or chewing, involves the jaw opening and closing, accomplished by muscles that move the mandible at the temperomandibular joint. The temporalis muscle originates on the temporal bone, passes medial to the zygomatic arch and inserts on the mandible on the anterior and medial aspects of the coronoid process. The masseter muscle arises on the zygomatic arch, passes lateral to the broad surface of the mandible, and inserts along the angle and lower part of the ramus of the mandible. The temporalis and masseter both elevate and retract the mandible. The buccinator muscle is a quadrilateral facial muscle located between the maxilla and mandible. It inserts on the orbicularis oris muscle and acts to flatten the cheek against the teeth, acting as an auxiliary mastication muscle holding the food between the teeth during mastication.

MUSCULAR SYSTEM

Deep muscles of mastication, lateral view

86 -7

KAPLAN) MEDICAL

86. Deep muscles of mastication, lateral view

a. Buccinator muscle

d. Zygomatic arch (cut)

b. Mandible

e. Lateral pterygoid muscle

c. Medial pterygoid muscle

The deep muscles of mastication are attached on the medial aspect

of the mandible. During mastication, the jaw is opened by action of the lateral pterygoid muscle. The lateral pterygoid originates on the sphenoid bone and inserts on the coronoid process of the mandible and on the articular disc of the temperomandibular joint. The lateral pterygoids act both to lower the mandible and to bring it forward. Closing of the jaw during chewing involves elevation of the mandible by actions of the masseter, temporalis, and medial pterygoid muscles. The medial pterygoid has two heads, one originating on the sphenoid bone and the other from the palatine bone. The muscle inserts on the medial side of the ramus of the mandible to elevate it. The medial

pterygoid and masseter work together, respectively, on the medial and lateral aspects of the mandible to raise it. Both the medial and lateral pterygoid muscles can also act to move the mandible side-to-side.

MUSCULAR SYSTEM

Muscles of the neck, anterior view

87

KAPLAN) MEDICAL ■

87. Muscles of the neck, anterior view

a. Hyoid bone

b. Superior belly of omohyoid muscle

c. Inferior belly of omohyoid muscle

d. Scapula

e. Manubrium of sternum f. Clavicle

g. Sternocleidomastoid muscle

h. Sternohyoid muscle

i. Mastoid process of temporal bone

Muscles in the neck control the position of the larynx, contribute to mastication and respiration, and support activities of the tongue and pharynx. The inferior belly of the omohyoid muscle arises on the scapula, runs parallel to the clavicle while being held in position by connective tissue, and the tendon then turns superiorly where it becomes the superior belly. The superior belly of the omohyoid inserts on the hyoid bone and acts to depress the larynx. The stemohyoid muscle also acts to depress the larynx; it originates on the manubrium of the sternum and inserts on the hyoid. The two heads of the stemocleidomastoid muscle arise on the sternum and clavicle and manubrium of the sternum; the muscle inserts on the mastoid process of the temporal bone. Acting separately, the sternocleidomastoids on each side rotate the head; acting together, they flex the neck and assist in respiration along with the scalene muscles.

,

MUSCULAR SYSTEM 1

88 7 Suprahyoid and infrahyoid muscles

of the neck, anterior view

KAPLA.2)1 MEDICAL ••■

88. Suprahyoid and infrahyoid muscles of the neck, anterior view

a. Mylohyoid muscle

h. Sternohyoid muscle

b. Mastoid process of temporal

i. Superior belly of omohyoid

bone

muscle

c. Thyroid cartilage

j. Stylohyoid

d. Sternothyroid muscle

k. Posterior belly of digastric

e. Scapula muscle

1. Sternum

I. Mandible

g. Inferior belly of omohyoid

m. Anterior belly of digastric

muscle muscle

Suprahyoid muscles are located above (superior to) the hyoid bone. The mylohyoid muscle is flat and triangular; it arises along the mandible and inserts on the hyoid bone. The mylohyoid forms the floor of the oral cavity and acts to raise the hyoid and lower the mandible. The digastric muscle opens the jaw (when the masseter and temporalis are relaxed); it inserts on the hyoid bone; the posterior belly originates on the mastoid process of the temporal bone, the anterior belly arises on the mandible. The stylohyoid muscle arises on the styloid process of the temporal bone, inserts on the hyoid bone and acts to elevate the larynx and aid in swallowing. The infrahyoid muscles include the omohyoid, stemohyoid, and stemothyroid, all of which insert on the hyoid and depress the larynx. The sternothyroid muscle arises on the posterior aspect of the sternum and inserts on the thyroid cartilage.

Prevertebral region and root of the neck, 89 anterior view

KAPLAN) MEDICAL

r

89. Prevertebral region and root of the neck, anterior view

a. Rectus capitis lateralis

muscle

b. Longus capitis muscle

c. Longus colli muscle

d. Levator scapulae muscle

e. Left rib

1. Second rib

g. Scapula

h. Sternum

i. Right rib

j. Posterior scalene muscle

k. Middle scalene muscle

1. Anterior scalene muscle

m. Carotid tubercle of sixth cervical vertebra

n. Transverse process of atlas

o. Rectus capitis anterior muscle

The scalene muscles of the neck arise on the transverse processes of the cervical vertebrae and insert on the first two ribs; they act to rotate the neck and to assist in respiration. The anterior scalene muscle originates on C3-6 and inserts on the first rib; the middle

scalene originates on C2-7 and also inserts on the first rib. The posterior scalene muscle arises on C4-6 and inserts on the second rib. The neck is flexed at the joint between the atlas and the occipital bone by several muscles that arise on the vertebrae and insert on the occipital bone. The longus capitus muscle arises from the transverse processes of C3-6, and inserts on the occipital bone to flex the neck. The small rectus capitis anterior and lateralis muscles both originate on the atlas (Ci) and insert on the occipital bone to flex the atlanto-occipital joint. The longus colli muscle originates both on the transverse processes of C3-7 and the vertebral body of Ti-3, inserts on C1-4, and acts to flex and rotate the neck. The levator scapulae muscle arises on C1-4 and inserts on the scapula to either raise the scapula or incline the neck toward that side.

Muscles of the neck, lateral view

90

KAPLAN) MEDICAL

90. Muscles of the neck, lateral view

a. Hyoid bone

b. Superior belly of omohyoid muscle

c. Sternothyroid muscle

d. Sternocleidomastoid muscle

e. Inferior belly of omohyoid muscle

1. Clavicle

g. First rib

h. Sternum

I. Occipital bone

j. Trapezius muscle

k. Levator scapulae muscle

I Middle scalene muscle

m. Anterior scalene muscle

n. Scapula

The trapezius is a broad, superficial muscle that originates along the dorsal midline, from the occipital bone, ligaments along the cervical vertebrae, or thoracic vertebrae. The muscle inserts on the acromion process and spine of the scapula as well as part of the clavicle. Its actions may include extension of the neck, elevation of the clavicle, or a variety of movements of the scapula. The levator scapulae extends between the cervical vertebrae and the scapula; it also elevates the scapula. The stemocleidomastoid muscle extends from the sternum and clavicle to the temporal bone and acts to flex or rotate the neck. The omohyoid and stemothyroid muscles arise on the scapula or sternum, respectively, and act to depress both the hyoid bone and the larynx. The anterior and middle scalene muscles originate on the cervical vertebrae and insert on the first rib; they rotate the neck and aid in respiration.

1 MUSCULAR SYSTEM

91 Neck, transverse section

KAPLAN) MEDICAL ......

91. Neck, transverse section

a. Sternocleidomastoid muscle h. Body of C5 vertebra

b. Anterior scalene muscle i. Sternothyroid muscle

c. Middle scalene muscle j. Sternohyoid muscle

d. Posterior scalene muscle k. Thyroid cartilage

e. Levator scapulae muscle L Pharynx

1. Trapezius muscle m. Platysma

g. Spinal cord

A transverse section of the neck shows the central spinal cord lying

posterior to the body of the C5 vertebra, and the anterior pharynx lying behind the larynx and its thyroid cartilage. The superficial

platysma is the most anterior of the muscles; lying between it and the thyroid cartilage are the stemothyroid and stemohyoid muscles that depress the larynx. Anteriolaterally, the stemocleidomastoid muscle extends from the sternum and clavicle to the mastoid process. Deep to this, the anterior, middle, and posterior scalene muscles extend from the cervical vertebrae to the first or second rib and act to flex the neck. Alongside the scalene muscles, the levator scapulae muscle acts to lift the scapula or bend the neck. On the posterior aspect of the neck, the broad, flat trapezius muscle is most superficial.

Lateral view

Superior view

i

KAPLAN) MEDICAL ......

Ocular muscles, lateral view and superior view 92

92. Ocular muscles, lateral view and superior view

a. Lateral rectus muscle e. Inferior oblique muscle

b. Superior rectus muscle f. Inferior rectus muscle

c. Levator palpebrae superioris g. Optic nerve muscle h. Medial rectus muscle

d. Superior oblique muscle I. Optic chiasma

The extrinsic eye muscles work together to produce movements of the eyeball. Four rectus muscles originate on the sphenoid bone near the optic nerve, and insert on the surface of the eyeball. They are the superior rectus muscle to move the eyeball to look up, the inferior rectus muscle to move the eyeball to look down, the medial rectus muscle to rotate the eyeball medially, and the lateral rectus muscle to rotate the eyeball laterally. The superior oblique muscle primarily rotates the eye medially, while the inferior oblique laterally rotates it; in addition, actions of the oblique muscles include depression and abduction, or elevation and abduction, respectively. The levator palpabrae superioris muscle extends from the sphenoid bone to the eyelid and acts to elevate and retract the eyelid.

Intrinsic muscles of the tongue, sagittal section 93

KAPLA MEDICAL --.

93. Intrinsic muscles of the tongue, sagittal section

a. Superior longitudinal muscle 1. Hyoid bone

of tongue g. Mylohyoid muscle b. Transverse lingual muscle h. Geniohyoid muscle c. Lingual tonsil; root of tongue i. Genioglossus muscle d. Cartilage of epiglottis I. Mandible e. Thyroid cartilage

The intrinsic muscles of the tongue are those that lie entirely within the tongue and act to alter the shape of the tongue for swallowing and talking. The superior longitudinal muscle lies just under the mucous membrane and runs from the root to the tip of the tongue and acts to shorten the upper surface of the tongue. The transverse lingual muscle arises along the lingual septum and inserts on the mucous membranes at the lateral margins of the tongue. At the posterior end of the tongue are lingual tonsils, masses of lymphatic tissue; the epiglottis lies at the opening to the pharynx. The floor of the oral cavity is formed by the mylohyoid muscle extending between the mandible and the hyoid bone; the geniohyoid muscle arises at the center of the mandible and inserts on the hyoid. The genioglossus muscle arises on the mandible and acts to protrude the tongue and depress its center.

Extrinsic muscles of the tongue, pharynx and larynx, lateral view

Pharynx, posterior view 95

KAPLA) MEDICAL ....

•

Superficial shoulder muscles, anterior view

MUSCULAR SYSTEM

Muscles of the shoulder, scapula and arm, 97 anterior view

!CAPLAN) MEDICAL

Deep muscles of the shoulder and arm, anterior view 98

Muscles with scapular attachments, posterior view 99

I(APLA) MEDICAL .... •

Muscles with scapular attachments, posterior view 99

KAPLA) MEDICAL ■

Superficial and intermediate muscles

100 of the back, posterior view

!CAPLAN) MEDICAL ....

MUSCULAR SYSTEM

Deep muscles of the back, posterior view 101

KAPLAN) MEDICAL

■

/

Anterior brachial muscles (flexors), lateral view

Posterior brachial muscles (extensors), lateral view 103

KAPLAii) MEDICAL ,..

104 Superficial flexor muscles of the forearm, anterior view

KAPLAN) MEDICAL ......

1

MUSCULAR SYSTEM

Superficial extensor muscles of the forearm, 105

lateral view (hand pronated)

ICAls...._1'1 MEDICAL

MUSCULAR SYSTEM

Deep flexor muscles of the forearm, anterior view 106

a

KAPLAJ) MEDICAL

a

MUSCULAR SYSTEM

Deep extensor muscles of the forearm, 107

posterior view

I(APLAN MEDICAL ....

MUSCULAR SYSTEM

Muscles of the hand, posterior (dorsal) view 109

I_AN MEDICAL

Muscles of the hand, anterior (palmar) view 110

KAPLA) MEDICAL ■.

Intercostal muscles, anterior view 111

KAPLAN) MEDICAL .,...

Diaphragm, anterior view

112

KAPLA MEDICAL

Superficial abdominal muscles, anterior view

114

KAPLAI,sI) MEDICAL

Deep abdominal muscles, anterior view 115

KAPLAN) MEDICAL "....

Posterior abdominal wall muscles, anterior view

116

KAPLAN) MEDICAL

a b

Pelvic diaphragm, superior view 117

KAPLAts)1 MEDICAL ...

Perineal muscles, inferior view 118

Male

h

KAPLAN) MEDICAL .....

Urogenital diaphragm, inferior view 119

!CAPLAN) MEDICAL

Lower limb muscles, anterior view 120

KAPLA MEDICAL ■

Muscles of the lower limb, posterior view

Superficial femoral muscles, anterior view

Deep femoral muscles, anterior view

Medial femoral muscles, medial view

g

Lateral femoral muscles, lateral view 125

KAPLAN) MEDICAL ....

k

MUSCULAR SYSTEM

Gluteal muscles, posterior view

126

KAPLAINI) MEDICAL ■

g

Posterior femoral muscles, posterior view 127

KAPLAN) MEDICAL

Posterior thigh and gluteal muscles, deep dissection, posterior view

1 128

KAPLAN) MEDICAL

a

Muscles of the anterior compartment

130 of the leg, anterior view

KAPLAN) MEDICAL .....

g

f

Muscles of the lateral compartment of the leg, 131 lateral view

KAPLAls MEDICAL

F MUSCULAR SYSTEM

Deep muscles of the leg, anterior view 132

KAPLAN) MEDICAL

-c

g

e

MUSCULAR SYSTEM

Muscles of the superficial posterior 133 compartment of the leg, posterior view

KAPLA) MEDICAL

MUSCULAR SYSTEM

Muscles of the deep posterior 134 compartment of the leg, posterior view

KAPLA) MEDICAL ......

Muscles of the dorsal foot

135

KAPLAN) MEDICAL

MUSCULAR SYSTEM

Plantar muscles of the foot, first and second layers 136

MEDICAL

Plantar muscles of the foot, third layer

137. Plantar muscles of the foot, third layer

a. Proximal phalanx of great toe

b. Flexor hallucis brevis muscle

c. Cuboid bone

d. Tendon of fibularis (peroneus) longus muscle

e. Adductor hallucis muscle, oblique head

1. Flexor digiti minimi brevis muscle

g. Adductor hallucis muscle, transverse head

h. Proximal phalanx

The flexor hallucis brevis muscle arises on the cuboid and lateral cuneiform tarsal bones, inserts on the proximal phalanx of the great toe, and flexes the great toe. The adductor hallucis muscle arises in two heads—the oblique on the base of metatarsals II—IV and the transverse on the plantar ligaments. The adductor hallucis inserts on the proximal phalanx of the great toe; it adducts and flexes the great toe. The flexor digits minimi brevis muscle arises at the base of metatarsal V. inserts on the lateral side of the proximal phalanx of toe 5, and flexes the metatarsophalangeal joint of toe 5. The tendon of the fibularis (peroneus) longus muscle crosses the sole of the foot obliquely and inserts at the base of the first metatarsal bone and on the medial cuneiform bone. It extends the foot and everts the sole of the foot.

71. Hip joint, frontal section

a. Coxal bone

d. Zona orbicularis of capsule b. Articular cartilage

e. Articular capsule c. Acetabular labrum

1. Femur

The hip joint is a sturdy synovial joint (ball and socket joint) between the globular head of the femur and the cup•like acetabulum of the coxal bone. A thin layer of articular cartilage covers both bone surfaces to reduce friction. A fibrocartilage lip called the acetabular labrum extends the edge of the acetabulum to increase its depth; it is located slightly beyond the widest diameter of the femoral head to hold it firmly in place. The articular capsule is strong and dense; it completely encloses the head and neck of the femur, and extends beyond the edge of the acetabulum. The capsule includes longitudinal bands of fibers that stretch between the hip bone and the femur to strengthen the joint; the zona orbicularis of the capsule includes deep circular fibers that form a collar to hold the head of the femur tightly in the socket. The joint permits a range of movements: flexion and extension, adduction and abduction, circumduction and rotation.

LII■limi■■•01

72. Pelvic ligaments, posterior view

a. Iliac crest

b. Posterior superior iliac spine

c. Iliolumbar ligament

d. Fifth lumbar vertebra

e. Supraspinous ligament

f. Short dorsal sacroiliac

ligaments

g. Long dorsal sacroiliac ligament

h. I.

I.

k.

I.

Femur

Sacrospinous ligament

Superficial dorsal

sacrococcygeal ligament

Sacrotuberous ligament

Articular capsule of the hip joint

Strong ligaments are necessary to stabilize the pelvis. The supraspinous ligament that runs along the edges of the vertebral dorsal spinous processes continues along the median sacral crest. In addition, the iliolumbar ligament connects the fifth lumbar vertebra both to the sacrum and the iliac crest. The sacroiliac joint is stabilized by the horizontal short dorsal sacroiliac ligament between the sacrum and the tuberosity of the ilium and by the oblique long dorsal sacroiliac ligament connecting the sacrum to the posterior superior iliac spine. The sacrotuberous ligament is connected at one end to the posterior inferior iliac spine, the lower part of the sacrum, and the coccyx; the other end attaches to the tuberosity and ramus of the ischium. Nearby, the sacrospinous ligament extends from the sacrum and coccyx to the spine of the ischium. The sacrococcygeal joint is stabilized by several ligaments, including the superficial dorsal sacrococcygeal ligament. At the hip joint, strong ligaments reinforce the articular capsule that encloses the head and much of the neck of the femur.

73. Knee joint, anterior view

a. Femur

b. Patella

c. Fibular collateral ligament (lateral collateral ligament)

d. Lateral meniscus

e. Lateral condyle of tibia

1. Fibula

g. Tibia

h. Tibial collateral ligament (medial collateral ligament)

I. Medial condyle of tibia

j. Medial meniscus

k. Patellar ligament

The articulation between the femur and tibia at the knee joint performs a simple hinge function, primarily facilitating flexion and extension of the lower leg. However, a small amount of medial and lateral rotation (io° and 3o° respectively) is also possible. The medial and lateral condyles of the femur articulate with the medial and lateral condyles of the tibia; the medial and lateral menisci are fibrocartilage pads that cushion and separate the bones within the joint. The patella is held in place anterior to the distal portion of the femur by the patellar ligament distally and the quadriceps muscle tendon proximally; it not only protects the knee joint but also provides increased leverage for the quadriceps muscle during knee extension. The patella resides at its most superior location during full extension of the knee, and moves as much as 7 cm inferiorly during flexion, until it is located between the distal ends of the femoral condyles. To the side, the knee joint is stabilized by the tibial (medial) collateral ligament and the fibular (lateral) collateral ligament.

74. Bent knee joint, anterior view with patella removed

a. Femur

b. Articular cartilage

c. Anterior cruciate ligament

d. Lateral meniscus

e. Lateral condyle of tibia

1. Fibula

g. Tibia h. Tibial collateral ligament

I. Medial condyle of tibia

j. Medial meniscus

k. Posterior cruciate ligament

With the knee bent and the patella removed, the interior of the synovial joint is revealed. The articular cartilage protecting the articular surface of the femur extends superiorly behind the position of the patella, as part of the femoropatellar joint. The two femoral condyles are separated from the two tibial condyles by the medial and lateral menisci. These pads of fibrocartilage fill in the space between the convex surface of the femoral condyle and the flatter surface of the tibial condyle; they act as durable shock absorbers and contribute to both stability and lubrication in the joint. Ligaments stabilize the joint; the anterior cruciate ligament (ACL) extends between the lateral condyle of the femur posteriorly and the intercondylar region of the tibia anteriorly; the posterior cruciate ligament (PCL) connects the posterior intercondylar region of the tibia with the medial condyle of the femur anteriorly. The ACL resists forces pushing the tibia forward, while the PCL resists forces pushing the tibia posteriorly relative to the femur. Excessive abduction or adduction motion at the knee joint is limited by the fibular (lateral) and tibial (medial) collateral ligaments.

75. Knee joint, sagittal section

a. Femur 1. Lateral meniscus, anterior

b. Lateral menniscus, horn

posterior horn g. Infrapatellar fat pad c. Fibula h. Patella d. Tibia I. Articular cartilage e. Patellar ligament

A sagittal section through the lateral condyles of the femur and tibia reveals the anterior-posterior relationships of the fully-extended knee joint. Articular cartilage covers the convex articular surface of the femur and the flatter articular surface of the tibia. Between the two articular cartilages lies the C-shaped lateral meniscus, with posterior and anterior horns positioned to fill the area between the curving articular surfaces. Popliteal ligaments strengthen the back of the synovial articular capsule. The fibula articulates with the tibial epicondyle laterally and posteriorly; a collateral ligament extends from the fibula to the lateral epicondyle of the femur to strengthen the joint. Anteriorly, the patella moves along the femoral articular surface when the quadriceps muscle flexes the knee; the articular cartilage of the patella is one of the thickest due to the intense stresses of this movement. The quadriceps muscle tendon attaches on the superior surface and is continuous with the inferior patellar ligament. The infrapatellar fat pad absorbs shocks and fills in the space below and behind the patella.

76. Ankle joint, posterior view

a. Fibula g. Calcaneal (Achilles) tendon

b. Posterior tibiofibular h. Calcaneus ligament i. Medial talocalcaneal

c. Transverse tibiofibular ligament ligament j. Talus

d. Posterior talofibular k. Deltoid ligament, ligament tibiocalcaneal part

e. Posterior talocalcaneal I. Deltoid ligament, tibiotalar ligament part

f. Calcaneofibular ligament m. Tibia

The posterior view of the ankle joint shows several ligaments that stabilize the articulations between the leg and ankle bones. The largest tendon in the human body is the calcaneal tendon (also known as the Achilles tendon) that connects three lower leg muscles—the gastrocnemius, the soleus, and the plantaris—with their insertion on the calcaneus, the largest of the tarsal bones. Above the ankle, the distal articulation of the tibia and fibula are stabilized by the posterior and transverse tibiofibular ligaments. Laterally, the ankle joint is stabilized by connections between the lateral malleolus of the fibula and the tarsal bones, including the talofibular and calcaneofibular ligaments. On the medial side, the ankle is stabilized by ligaments connecting the medial malleolus of the tibia with tarsal bones such as the calcaneus and the talus, including the tibiocalcaneal and tibiotalar parts of the deltoid ligament. Articulations between the tarsal bones are also stabilized by ligaments, such as the medial and posterior talocalcaneal ligaments connecting the talus and calcaneus.

104. Superficial flexor muscles of the forearm, anterior view

a.

b.

c.

d.

e.

1.

Palmaris longus muscle

Humerus

Flexor carpi radialis muscle

Pronator teres muscle

Flexor carpi ulnaris muscle

Flexor digitorum superficialis muscle

g. h.

I.

J. k.

l.

m.

Radius

Ulna

Second metacarpal bone

Pisiform bone

Hamate bone

Fifth metacarpal bone

Middle phalanx

The palmaris longus muscle arises on the medial epicondyle of the humerus and flexes the wrist by inserting on the palm and a band of connective tissue in the wrist called the flexor retinaculum. The flexor carpi radialis muscle arises on the medial epicondyle of the humerus, inserts at the base of the second and third metacarpal bones, and both flexes and abducts the wrist. The flexor carpi

ulnaris muscle originates on the medial epicondyle of the humerus as well as adjacent parts of the ulna; it inserts on the pisiform and hamate carpal bones, and on the fifth metacarpal bone. The flexor

carpi ulnaris both flexes and adducts the wrist. The flexor digitorum superficialis muscle arises on the medial epicondyle of the humerus

as well as adjacent surfaces of the ulna and radius; it inserts on the middle phalanges of fingers 2-5 by long tendons and acts to flex the fingers at the joints between the metacarpals and proximal phalanges as well as the joint between the proximal and middle phalanges.

The pronator teres muscle arises on the medial epicondyle of the humerus as well as the coronoid process of the ulna, inserts on the

lateral, distal surface of the radius, and pronates the forearm.

105. Superficial extensor muscles of the forearm, lateral view (hand pronated)

a. Lateral epicondyle of g. Distal phalanx humerus h. Second metacarpal bone

b. Ulna i. Radius c. Extensor digitorum muscle j. Extensor carpi radialis brevis d. Extensor carpi ulnaris muscle

muscle k. Extensor carpi radialis e. Extensor digiti minimi longus muscle

muscle l. Brachioradialis muscle f. Extensor expansion

The brachioradialis muscle arises on the ridge above the lateral epicondyle of the humerus, inserts on the lateral, distal part of the radius and flexes the forearm at the elbow. The extensor carpi radialis brevis and extensor carpi radialis longus muscles flex the wrist; the brevis originates on the ridge above the lateral epicondyle of the humerus and inserts at the base of the second metacarpal bone, the longus arises on the lateral epicondyle of the humerus, inserts at the base of the third metacarpal, and abducts as well as extends the wrist. The extensor carpi ulnaris muscle arises on both the lateral epicondyle of the humerus and adjacent surfaces of the ulna, inserts at the base of the fifth metacarpal, and both extends and adducts the wrist. The extensor digitorum muscle arises on the lateral epicondyle of the humerus and its tendons insert on the phalanges of fingers 2-5; it extends those four fingers as well as extending the wrist. The extensor digiti minimi muscle arises by tendon from the lateral epicondyle of the humerus, inserts on the extensor expansion of finger 5 and extends that finger at all joints.

106. Deep flexor muscles of the forearm, anterior view

a. Humerus

b. Ulna

c. Flexor digitorum profundus muscle

d. Pronator quadratus muscle

e. Distal phalanges

f. Flexor pollicis longus

g. Radius

The flexor digitorum profundus muscle originates on the olecranon and other proximal portions of the ulna; it inserts with four long

tendons on the distal phalanges to flex the joint between the middle

and distal phalanges. The flexor pollicis longus muscle arises along

the shaft of the radius and inserts on the distal phalanx of the thumb

to flex the joints of the thumb. The pronator quadratus muscle arises on the distal quarter of the ulna and inserts on the corresponding portion of the radius; it pronates the forearm as well as maintains the positions of the radius and ulna in relation to each other.

107. Deep extensor muscles of the forearm, posterior view

a. Ulna

b. Extensor pollicis longus muscle

c. Extensor indicis muscle

d. Extensor expansion of index finger

e. Distal phalanx

1. Radius g. Extensor pollicis brevis

muscle

h. Abductor pollicis longus muscle

I. Supinator muscle

The relative positions of the radius and ulna control hand position; in the supine position, the palm of the hand faces forward. The supinator muscle arises on the lateral epicondyle of the humerus and adjacent parts of the ulna, passes dorsal to the radius and inserts on its lateral surface; it works in supination along with the biceps brachii. The abductor pollicis longus muscle arises on the posterior surfaces of the radius and ulna, inserts on the first metacarpal and trapezium bones, and acts to abduct and extend the thumb. The extensor pollicis longus muscle originates on the ulna, inserts on the distal phalanx of the thumb, and extends the thumb. The extensor pollicis brevis muscle arises on the radius, inserts on the proximal phalanx of the thumb and extends the thumb. The extensor indicis muscle arises on the ulna, inserts on the extensor expansion of the second metacarpal and extends the index finger.

108. Transverse sections of the arm

a. Biceps brachii muscle

b. Brachialis muscle

c. Humerus

d. Triceps muscle, lateral head

e. Triceps muscle, long head

f. Triceps muscle, medial head

g. Tendons of flexor digitorum superficialis muscle

h. Tendon of flexor carpi radialis muscle

i. Tendon of flexor pollicis

longus muscle

j. Tendon of abductor pollicis longus muscle

k. Tendon of extensor pollicis brevis muscle

I. Radius

m. Tendon of extensor carpi radialis longus muscle

n. Tendon of extensor carpi

radialis brevis muscle

o. Tendon of extensor pollicis longus muscle

p. Tendons of extensor digitorum muscle

q. Tendon of extensor digiti minimi muscle

r. Tendon of extensor carpi ulnaris muscle

s. Ulna

t. Pronator quadratus muscle

u. Tendon of flexor carpi ulnaris

muscle

v. Tendons of flexor digitorum profundus muscle

The relative positions of the arm muscles are seen in the upper arm. The biceps brachii and brachialis muscles are anterior to the humerus and flex the elbow joint; the three portions of the triceps muscle act together to extend the elbow. Most of the forearm muscles

occupy the proximal portion of the forearm, while their tendons extend distally to control wrist, hand and finger motion. Anterior to the ulna and radius are the tendons of Flexor muscles, while the tendons of extensor muscles are posterior to the two bones. The pronator quadratus muscle extends between the radius and ulna, acting to pronate the forearm and to bind the two bones together.

109. Muscles of the hand, posterior (dorsal) view

a. Insertion of lateral slips of extensor digitorum muscle and interosseous and lumbrical muscles

b. Third interosseous muscle

c. Tendons of extensor digiti minimi muscle

d. Tendon of extensor carpi ulnaris muscle

e. Extensor retinaculum

f. Tendon of extensor carpi radialis brevis muscle

g. Tendon of extensor carpi radialis longus muscle

h. Tendon of extensor indicis muscle

I. Tendons of extensor digitorum muscle

j. First interosseous muscle

k. Extensor expansion

L Insertion of central slip of extensor digitorum muscle

The extensor retinaculum is a wide band of connective tissue along the wrist; it holds tendons in place as they extend from muscles in the forearm to their insertion points in the hand. Each of the four tendons of the extensor digitorum muscle spreads out across the joint at the base of the proximal phalanx to form a broad hood called the extensor expansion, continues along the proximal phalanx, then splits to form a central slip that inserts on the middle phalanx and two lateral slips that pass along the side of the first interphalangeal joint. The two lateral slips rejoin and insert on the distal phalanx along with tendons from the interosseous and lumbrical muscles. The tendons of the extensor indicis and extensor digiti minimi muscles parallel those of the extensor digitorum to insert on the second and fifth finger, respectively. The tendons of the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris insert on the base of the second, third, and fifth metacarpals, respectively. Interosseous muscles are bipennate muscles that originate along the sides of the metacarpals and insert on the extensor expansions, acting to abduct the fingers.

.111....

110. Muscles of the hand, anterior (palmar) view

a. Tendons of flexor digitorum profundus muscle

b. Tendons of flexor digitorum superficialis muscle

c. First and second lumbrical muscles

d. Proximal phalanx

e. Adductor pollicis muscle

1. Flexor pollicis brevis muscle

g. Abductor pollicis brevis muscle

h. Flexor retinaculum

I. Pisiform bone

I. Abductor digiti minimi muscle

k. Flexor digiti minimi brevis muscle

1. Opponens digiti minimi

muscle

m. Fourth and fifth lumbrical muscles

n. Proximal phalanx

The tendons of the flexor digitorum superficialis muscle are stabilized at the wrist as they pass under the flexor retinaculum, and insert on the middle phalanges. The tendons of the flexor digitorum profundus muscle are deeper at the wrist and palm, but pass through the superficial tendons to insert on the distal phalanx. On the lateral (thumb) side of the hand, the adductor pollicis, flexor pollicis brevis and abductor pollicis brevis muscles insert on the proximal phalanx of the thumb to control its movements. On the medial side of the hand, the abductor digiti minimi and flexor digiti minimi muscles arise on the pisiform and hamate bones respectively, insert on the proximal phalanx, and act to abduct or flex the little finger. The opponens digit! minimi muscle acts to bring the little finger in opposition with the thumb. Four wormlike lumbrical muscles extend between the tendons of the flexor digitorum profundus and the extensor expansions (dorsal) to simultaneously flex the metacarpophalangeal joints and extend the interphalangeal joints.

111. Intercostal muscles, anterior view a. External intercostal muscle d. Costal cartilage b. First rib e. Internal intercostal muscle c. First thoracic vertebra

Respiration involves changes in pressure within the thoracic cavity due to movements of the ribs and diaphragm that change the volume of the cavity. The intercostal muscles extend between the ribs and function in the respiratory movements of the ribs. Eleven external intercostal muscles on each side arise from the inferior border of ribs 1-11 and act to lift the rib during inspiration. The external intercostals pass obliquely forward and down to insert on the next lower rib, ranging from the tubercles posteriorly to the end of the ribs anteriorly, except that the lower two extend to the costal cartilage and the upper two don't quite reach the end of the rib. Eleven internal intercostal muscles on each side originate at the costal groove on the interior, inferior surface of ribs 1-11, pass obliquely down and laterally to insert on the superior margin of the next lower rib. They bring the ribs closer together during exhalation.

112. Diaphragm, anterior view

a. Xiphoid process

e. Medial arcuate ligament

b. Esophageal hiatus

f. Left crus of diaphragm

c. Diaphragm

g. Right crus of diaphragm

d. Aortic hiatus

h. Third lumbar vertebra

The diaphragm is a broad, thin dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The muscle originates laterally and anteriorly around the inferior margin of the rib cage and costal cartilages, as well as the posterior aspect of the xiphoid process of the sternum. Posteriorly, the diaphragm arises from the medial arcuate ligament, allowing the psoas major muscle to pass vertically along the body wall. Muscular fibers of the right crus of the

diaphragm arise on vertebrae I.1-3, while the left crus arises on 11-2;

the median arcuate ligament unites the two crura and passes over the

aortic hiatus. Openings in the diaphragm allow important structures

to be continuous between the two cavities; these openings include the esophageal hiatus and the aortic hiatus. The diaphragm plays an important role in respiration; contraction of the muscle causes the "dome" to move inferiorly, expanding the thoracic cavity and triggering inhalation by reducing intrathoracic pressure. Relaxation of the diaphragm allows it to return to a convex shape that makes the thoracic cavity smaller; elasticity of the lungs then expels air.

113. Diaphragm, inferior view

a. Costal cartilage

f. Lateral arcuate ligament and

b. Esophageal hiatus

twelfth rib

c. Aortic hiatus g. Medial arcuate ligament

d. Diaphragm

h. Vena caval foramen

e. First lumbar vertebra

i. Central tendon of diaphragm

Muscle fibers of the diaphragm arise from the medial arcuate ligament attached to the transverse process of vertebra Li, the lateral arcuate ligament along the twelfth rib, the interior surface of the anterior and lateral parts of the inferior ribs and costal cartilage, and the posterior surface of the sternum at the xiphoid process. Anterior to the lumbar vertebrae, muscle fibers of the right and left crura arise and pass to either side of the aortic hiatus, an opening behind the fibers of the diaphragm that allows passage of the abdominal aorta from the thoracic cavity to the abdomen. Other openings in the diaphragm include the esophageal hiatus for passage of the esophagus toward the stomach, and the vena caval foramen that allows the posterior vena cava to return toward the heart. The muscle fibers of the diaphragm converge on the central tendon, which has no skeletal attachment, but is fused on its superior surface with the pericardium.

114. Superficial abdominal muscles, anterior view

a. Sternum

b. Cut edge of aponeurosis, external abdominal oblique muscle

c. Aponeurosis, internal abdominal oblique muscle

d. Internal abdominal oblique muscle

e. Inguinal ligament

f. Pubic tubercle

g. Symphysis pubis

h. Spermatic cord

I. Umbilicus

I. External abdominal oblique muscle

k. Aponeurosis, external abdominal oblique muscle

L Fifth rib

The external abdominal oblique muscle is the most superficial of the muscles in the torso wall. It is a broad, flat muscle that arises on the anterior angles of the inferior eight ribs and inserts on the pubic tubercle, the inguinal ligament, and the iliac crest. The fibers of the broad, flat internal abdominal oblique muscle run perpendicular and deep to the fibers of the external abdominal oblique. The internal abdominal oblique arises on the fascia of the lower back, the iliac crest and the inguinal ligament and inserts on the inferior border of the lower three ribs and on the linea alba. Both abdominal oblique muscles end in broad aponeuroses that together form the anterior wall of the abdomen. Near the inguinal ligament, a triangular hole in the aponeurosis provides for passage of the spermatic cord (in males) or the round ligament of the uterus (in females). Acting together, the two abdominal oblique muscles on each side compress the abdomen, aiding in breathing and defecation, or flex the trunk. Acting separately, they rotate the trunk.

115. Deep abdominal muscles, anterior view

a. Sternum

b. Fifth rib

c. Tendinous intersection

d. Rectus abdominis muscle

e. Arcuate line 1. Symphysis pubis

g. Aponeurosis of transversus abdominis muscle

h. Iliac crest

i. Transversus abdominis muscle

j. Umbilicus

k. Cut edges of rectus abdominis muscle

The transversus abdominis muscle lies deep to the internal and external abdominal oblique muscles and works with them to compress the abdomen. The transversus abdominis originates on the iliac crest, the inguinal ligament and the costal cartilage of ribs 7-12. The aponeurosis of the transversus abdominis inserts on the linea alba. The rectus abdominis muscle extends vertically along either side of the linea alba, and acts to depress the ribs, flex the spine and stabilize the pelvis during walking. It originates along the symphysis pubis and inserts on the costal cartilages of ribs 5-7 and the xiphoid process of the sternum. Inferior to the arcuate line, the aponeurosis of the other abdominal muscles is superior to the rectus abdominus; superficial to the arcuate line, parts of the aponeurosis lie both superficial and deep to the rectus abdominis, forming a sheath that encloses the muscle. At several tendinous intersections, the rectus abdominis muscle is firmly attached to the part of the sheath that stretches anterior to the muscle.

116. Posterior abdominal wall muscles, anterior view

a. Diaphragm g. Iliacus muscle

b. Lateral arcuate ligament h. Iliolumbar ligament

c. Quadratus lumborum muscle i. Umbilicus

d. Lumbar vertebrae j. Psoas major muscle

e. Iliac crest k. Medial arcuate ligament

1. Femur

The quadratus lumborum muscle arises from the iliac crest and the iliolumbar ligament, which extends between the transverse processes of the 5th lumbar vertebra and the iliac crest. The quadratus lumborum passes under the edge of the diaphragm at the lateral arcuate ligament and inserts on the lowest rib and the transverse processes of lumbar vertebrae 1-4; together, the two quadratus lumborum muscles act to depress the rib cage and individually each flexes the spine laterally. The psoas major muscle originates on the transverse processes and bodies of the lumbar vertebrae, passes under the edge of the diaphragm at the medial arcuate ligament, and inserts on the lesser trochanter of the femur. The iliacus muscle arises on the concave superior surface of the ala of the ilium, and its fibers join the tendon of the psoas major to insert on the lesser trochanter of the femur. The psoas major and the iliacus are part of a group of muscles known as hip flexors—they flex the hip and laterally rotate the thigh.

117. Pelvic diaphragm, superior view

a. Coccyx g. Symphysis pubis b. Coccygeus muscle h. Hiatus of urethra c. Anal canal i. Obturator internus muscle, d. Levator ani muscle, and overlying obturator fascia

iliococcygeus j. Tendinous arch for origin of e. Levator ani muscle, levator ani muscle

pubococcygeus f. Levator ani muscle,

puborectalis

Looking down on the pelvis from the abdomen, one can see the pelvic diaphragm that separates the pelvic cavity from the perineal region and supports the pelvic viscera including bladder and intestines. The coccygeus muscle arises on the spine of the ischium and the sacrospinous ligament, and widens to insert along the coccyx. The levator ani muscle consists of three parts: the iliococcygeus extends from the ischial spine and adjacent tendinous arch of the pelvic fascia to the coccyx; the pubococcygeus stretches from the pubic bone to the coccyx and surrounds the urethra; and the puborectalis arises from the symphysis pubis, surrounds the anal canal and meets with corresponding fibers from the opposite side to support the rectum. The obturator intemus muscle is covered by an overlying fascia; the muscle originates on the fascia as well as the adjacent margins of the pubis and ischium. The obturator internus inserts on the greater trochanter of the femur and rotates the thigh laterally.

118. Perinea( muscles, inferior view a. Coccyx b. Anococcygeal ligament

c. Levator ani muscle

d. Ischia' tuberosity

e. Ischiocavernosus muscle

f. Bulbocavernosus (bulbospongiosus) muscle

g. Central tendinous point of perineum

h. Inferior fascia, urogenital diaphragm

i. Superficial transverse perinea( muscle

I. External anal sphincter muscle

k. Urogenital hiatus

The levator an! muscle extends from the surface of the lower pelvis to the coccyx and the midline; those fibers anterior to the coccyx join with the fibers from the opposite side to form the anococcygeal ligament. The external anal sphincter muscle is an elliptically-shaped group of muscle fibers that surrounds the anus; external fibers arise on the anococcygeal ligament and insert on the central tendinous point of the perineum and deeper fibers form a complete sphincter. The superficial transverse perinea( muscle also inserts on the central tendinous point of the perineum. The ischiocavemosus muscle arises on the ischial tuberosity and ramus and inserts on the pubic symphysis. The ishiocavernosus compresses and stiffens the penis (in males) or clitoris (in females). The bulbospongiosus (or bulbocavernosus) muscle originates on the collagen sheath at the base of the penis (in males) or the clitoris (in females); the fibers cross over the urethra (in males) or the urethra and vagina (in females) and insert on the central tendinous point of the perineum. The bulbospongiosus acts in males to stiffen the penis and eject urine or semen; in females, the muscle stiffens the clitoris and narrows the urogenital hiatus or vaginal opening.

119. Urogenital diaphragm, inferior view

a. Superficial transverse perineal muscle

b. Deep transverse perineal

muscle

c. Sphincter urethrae muscle

d. Symphysis pubis

e. Arcuate pubic ligament

f. Transverse perineal ligament

g. Urethra

h. lschial tuberosity

i. Vagina

The urogenital diaphragm refers to the thin layer of muscle at the outlet of the pelvis. Posterior and inferior to the symphysis pubis, the arcuate pubic ligament is a thick, triangular ligament connecting the two pubic bones. The transverse perineal ligament is a region of thickened fascia between the urogenital diaphragm and the arcuate pubic ligament. The deep transverse perineal muscle arises on the ischial ramus, and inserts at the central tendinous point of the perineum. The small superficial transverse perineal muscle extends transversely between the ischial tuberosity and the central tendinous point of the perineum. The sphincter urethrae muscle arises from the inferior pubic ramus; fibers from both sides meet to form a sphincter that constricts the urethra in the male and compresses both the urethra and vagina in the female.

qr

120. Lower limb muscles, anterior view

Anterior femoral muscles: a. Sartorius muscle

b. Rectus femoris muscle

c. Vastus medialis muscle

d. Vastus lateralis muscle

Medial femoral muscles:

e. Pectineus muscle

f. Adductor longus muscle

g. Gracilis muscle

Lateral compartment muscles: h. Fibularis (peroneus) longus

muscle

i. Fibularis (peroneus) brevis muscle

Anterior compartment muscles: j. Tibialis anterior muscle

k. Extensor digitorum longus

muscle

I. Extensor hallucis

longus muscle

Posterior compartment muscles:

m. Gastrocnemius muscle

n. Soleus muscle

Lateral femoral muscles:

o. Tensor fasciae latae muscle

The tensor fasciae latae muscle flexes the hip. Anterior femoral muscles include the sartorius muscle that flexes the knee and the rectus femoris, vastus lateralis and vastus medialis muscles that extend the knee.

Medial femoral muscles include the pectineus and adductor longus

muscles that flex, adduct and medially rotate the hip; and the gracilis muscle that also flexes the knee. On the lateral side of the lower leg, the Fibularis longus and Fibularis brevis muscles evert the foot and

plantar flex the ankle. The anterior side of the lower leg includes the

tibialis anterior muscle that dorsiflexes the ankle and inverts the foot; and the extensor digitorum longus and extensor hallucis longus

muscles that extend the joints of the toes. On the posterior side of the lower leg are the gastrocnemius and soleus muscles that plantar flex the ankle and adduct the foot; the gastrocnemius also flexes the knee.

110•1111=111111MOL. MIL‘la:77 • ■ i

121. Muscles of the lower limb, posterior view

Posterior femoral muscles: a. Biceps femoris muscle

b. Semitendinosus muscle

c. Semimembranosus muscle

Superficial posterior compartment of the leg: d. Plantaris muscle

e. Gastrocnemius muscle

Lateral femoral (glutea0 muscles: 1. Gluteal fascia over gluteus

medius muscle

g. Gluteus maximus

Medial femoral muscles: h. Adductor magnus muscle

i. Gracilis muscle

j. Calcaneal tendon

k. Iliotibial tract

The superficial gluteus maximus muscle extends and laterally rotates the hip, while the deeper gluteus medius muscle abducts and medially rotates the hip. Along with other muscles, the gluteus maximus inserts on the iliotibial tract, a layer of fascia that lies posterior to the tensor fasciae latae muscle, interconnecting the femur, patella and tibia, and stabilizing the knee. On the medial side, the adductor magnus muscle abducts the hip; portions of the muscle also flex and medially rotate or extend and laterally rotate the hip. The gracilis muscle adducts and medially rotates the hip as well as flexing the knee. Other femoral muscles that flex the knee include the semitendinosus muscle, the biceps lemon's muscle that also extends and laterally rotates the hip, and the semimembranosus muscle that also flexes and medially rotates the hip. The gastrocnemius muscle flexes the knee, plantar flexes the ankle, and adducts the foot. The plantaris muscle inserts on the calcaneal tendon to flex the knee and plantar flex the ankle.

122. Superficial femoral muscles, anterior view

Abdominal muscles related to the leg: a. Psoas major muscle

b. lliacus muscle

Anterior femoral muscles: c. Sartorius muscle

Quadriceps femoris muscle:

d. Rectus femoris

e. Vastus lateralis

f. Vastus medialis

Medial femoral muscles: g. Pectineus muscle

h. Gracilis muscle

I. Adductor longus muscle

j. Inguinal ligament

k. Tendon of rectus femoris muscle

1. Patella

m. Pubic tubercle

n. Pecten pubis

The psoas major muscle originates on the lumbar vertebrae while the iliacus muscle arises on the broad, concave superficial surface of the ilium; both muscles insert on the lesser trochanter of the femur and flex the hip. The quadriceps femoris muscle is composed of four muscles that attach at the patella and continue as the patellar ligament to insert on the tibial tuberosity and act to extend the knee. The rectus femoris arises on the ilium; it flexes the hip as well as the knee. The vastus medialis, vastus lateralis and the vastus intermedius all originate on the femur. Like the rectus femoris, the sartorius muscle arises on the iliac spine; it inserts on the tibia and flexes the knee as well as flexing and laterally rotating the hip. Three medial femoral muscles adduct and rotate the hip medially. The adductor longus muscle arises on the ramus of the pubis and the pectineus muscle originates along the pectin pubis, a ridge on the superior side of the ramus of the pubis bone; both insert along the femur and also flex the hip. The gracilis arises on the ramus of the pubis, inserts on the tibia and also flexes the knee.

123. Deep femoral muscles, anterior view

a. Pecten pubis

Medial femoral muscles: b. Obturator externus muscle

c. Adductor brevis muscle

d. Adductor magnus muscle

e. Gracilis muscle

Anterior femoral muscle: f. Vastus intermedius muscle

g. Adductor hiatus

h. Patella

I. Iliofemoral ligament

j. Greater trochanter of femur

The vastus intermedius muscle is deep to the rectus femoris; it arises on the upper part of the femur, inserts on the patella along with the other quadriceps tendons, continuing on as the patellar ligament, and acts to flex the knee. The obturator extemus muscle arises on the obturator foramen, inserts on the fossa medial to the greater trochanter on the posterior side of the femur and rotates the hip laterally. The adductor brevis and adductor magnus muscles originate on the inferior ramus of the pubis and insert on the femur; both adduct the hip. In addition, the adductor brevis flexes the hip while different portions of the adductor magnus may either flex or extend the hip. The adductor hiatus is a space near the insertion of the adductor magnus where blood vessels pass. The gracilis muscle also arises on the inferior ramus of the pubis; it inserts on the medial surface of the tibia below the medial condyle, and both flexes the knee and adducts the hip.

124. Medial femoral muscles, medial view

a. Right hip bone

Medial femoral muscles: b. Pectineus muscle

c. Obturator externus muscle

d. Adductor longus muscle

e. Gracilis muscle

1. Adductor magnus muscle

g. Femur

h. Tibia

On the medial aspect of the thigh, the most superficial muscle is the gracilis; it extends from the pubis part of the hip bone to the tibia and flexes the knee as well as adducts the hip. The adductor magnus is a large, powerful muscle that arises on the pubis and ischium and inserts along the femur. The adductor magnus adducts the hip; in addition, the superior portion flexes the thigh while the inferior portion extends it. The adductor longus and pectineus muscles extend between the pubis bone and the femur; they act to flex and adduct the hip, and assist in medial rotation. The obturator extemus muscle extends between the margin of the obturator foramen and the posterior surface of the greater trochanter of the femur; it rotates the thigh laterally as well as assists in adduction.

125. Lateral femoral muscles, lateral view

Lateral femoral (gluteal) muscles: a. Gluteus medius muscle

b. Gluteus maximus muscle

c. Tensor fasciae latae muscle

d. Iliotibial tract

e. Femur

1. Tibia

g. Iliac crest

On the lateral aspect of the hip, the gluteus maximus muscle is the most superficial of the gluteal muscles; it arises along the posterior

iliac crest, the sacrum and the coccyx. The fibers of the gluteus maximus pass inferiorly and laterally to insert on the iliotibial tract—a band of collagen tissue that passes down along the thigh to insert on the tibia. The gluteus maximus is the major extensor of the hip joint and also acts in lateral rotation. The deeper gluteus medius muscle originates on the ilium, below the iliac crest, and inserts on the greater trochanter of the femur. The gluteus medius is the major abductor of the hip; portions of it may assist in rotating the hip either medially or laterally. The tensor fasciae latae muscle arises on the anterior iliac crest and the fasciae lata, and inserts on the iliotibial tract. The tensor fasciae latae abducts the thigh and rotates the hip medially.

126. Gluteal muscles, posterior view

a. Posterior superior iliac spine

b. Gluteus medius muscle

c. Piriformis muscle

d. Superior gemellus muscle

e. Obturator internus muscle

f. Greater trochanter of femur

g. Inferior gemellus muscle

h. Quadratus femoris muscle

i. Lesser trochanter of femur

j. Sacrotuberous ligament

k. Iliotibial tract

I Glluteus maximus muscle

m. Gluteal fascia

The superficial gluteus maximus muscle arises on the iliac crest, inserts

on the iliotibial tract, and is a major extensor of the hip. Deep to the

gluteus maximus, the gluteus minimus arises from the ilium, inserts on

the greater trochanter of the femur, and abducts the hip. The piriformis muscle originates on the anterior part of the sacrum and inserts on the greater trochanter of the femur; it rotates the hip laterally. The superior gemellus muscle arises on the spine of the ischium, the obturator internus muscle originates on the obturator foramen and the inferior gemellus muscle arises on the ischial tuberosity. These three muscles insert together on the greater trochanter of the femur and rotate the hip laterally. The quadratus femoris muscle arises on the ischium, inserts on the posterior surface of the femur between the greater and lesser trochanters, and also rotates the hip laterally.

127. Posterior femoral muscles, posterior view

a. Femur

b. Biceps femoris muscle

c. Fibula

d. Tibia

e. Semimembranosus muscle

1. Semitendinosus muscle

g. Tuberosity of ischium

On the posterior aspect of the thigh, the long head of the biceps femoris muscle arises on the posterior surface of the ischial tuberosity, and the deeper short head arises midway down the femur, along the

linea aspera. The two heads unite and insert together on the apex on the head of the fibula and on the lateral tibial condyle. It flexes the knee as well as extending the thigh. The semimembranosus muscle arises on the ischial tuberosity and inserts on the medial condyle of the tibia; it extends the thigh, flexes the knee, and rotates the tibia medially. The more superficial semitendinosus muscle originates on the ischial tuberosity and inserts on the medial side of the tibia shaft; it flexes and medially rotates the knee, and extends the thigh.

128. Posterior thigh and gluteal muscles, deep dissection, posterior view

a. Gluteus minimus muscle g. Tibia

b. Inferior gemellus muscle h. Semimembranosus muscle

c. Quadratus femoris muscle i. Adductor magnus muscle

d. Linea aspera of femur j. Obturator internus muscle

e. Biceps femoris muscle, k. Superior gemellus muscle short head I. Piriformis muscle

f. Fibula

The gluteus minimus lies deep to the gluteus medius; it arises on the outer surface of the ilium, inserts on the greater trochanter of the femur, and abducts the hip. The piriformis, superior gemellus, obturator internus, inferior gemellus and quadratus femoris muscles

arise along the pelvis, insert on or near the greater trochanter of the femur, and rotate the thigh laterally. A deep view of the posterior thigh muscles shows the short head of the biceps femoris, as it arises along the linea aspera, a ridge of roughened surface that runs longitudinally along the posterior surface of the femur. The short head is joined by the long head of the biceps femoris that arises

on the ischium and both parts insert together on the fibula and the lateral condyle of the tibia. The adductor magnus muscle arises on

the hip bone and inserts along the length of the linea aspera, and both adducts and medially rotates the hip. The semimembranosus muscle arises on the ischium, inserts on the medial tibial condyle, and flexes the knee, extends the thigh, and rotates the tibia medially.

129. Thigh, transverse section

a. Rectus femoris muscle I. Semitendinosus muscle

b. Femur j. Semimembranosus muscle

c. Vastus medialis muscle k. Biceps femoris muscle, long

d. Femoral artery head

e. Femoral vein I. Biceps femoris muscle, short

f. Sartorius muscle head

g. Gracilis muscle m.Vastus lateralis muscle

h. Adductor magnus muscle n. Vastus intermedius muscle

A transverse section of the thigh, shown a short distance above the knee, illustrates the relative positions of the femoral muscles.

Anterior to the femur lies the vastus medialis, vastus intermedius, and vastus lateralis muscles. Most superficial on the anterior aspect is the rectus femoris. These anterior muscles all insert on the patella and act to extend the knee. On the posterior-lateral side of the femur are the short head and long head of the biceps femoris. Between the biceps femoris and the large adductor magnus muscles are the superficial semitendinosus and the deeper semimembranosus muscles; they flex the knee. On the medial aspect are the gracilis and sartorius muscles; they, too, flex the knee. Because of the unique combination of origin and insertion for each, some of these muscles also rotate the hip either medially or laterally, or adduct the hip. The femoral artery and vein both lie deep within the thigh muscles.

130. Muscles of the anterior anterior view

a. Lateral condyle of tibia

b. Head of fibula

c. Tibialis anterior muscle

d. Extensor digitorum longus muscle

e. Extensor hallucis longus

muscle

1. Lateral malleolus

g. Tendon of fibularis (peroneus) brevis muscle

compartment of the leg,

h. Tendons of extensor digitorum longus muscle

i. Inferior extensor retinaculum

j. Medial malleolus

k. Tendon of tibialis anterior muscle

1. Tendon of extensor hallucis longus muscle

m. Distal phalanx

In anatomical terms, the lower limb is divided into two regions—the thigh above the knee and the leg below the knee. The anterior compartment of the leg has several muscles involved in dorsiflexion, or movement of the foot to decrease the angle between the foot and leg. The tibialis anterior muscle arises on the lateral condyle of the tibia, and its tendon inserts on the medial cuneiform tarsal and first metatarsal bones. The extensor digitorum longus muscle originates on the lateral condyle of the tibia and the anterior surface of the fibula;

its tendons insert on the superior surface of the phalanges of toes 2-5 and it extends the toes in addition to dorsiflexion of the foot. The extensor hallucis longus muscle originates on the fibula and its tendon inserts on the distal phalanx of the great toe; it extends the great toe in addition to dorsiflexion of the foot. The inferior extensor retinaculum is a band of collagen fibers that extends from the calcaneus laterally to the medial malleolus of the tibia; it stabilizes the synovial sheaths for the tendons of the fibularis brevis, tibialis anterior, extensor digitorum longus, and extensor hallucis longus as they cross the ankle joint.

131. Muscles of the lateral lateral view

a. Fibularis (peroneus) longus muscle

b. Fibularis (peroneus) brevis muscle

c. Lateral malleolus

d. Tendon of peroneus brevis muscle

compartment of the leg,

e. Fifth metatarsal bone

1. Tendon of peroneus longus muscle

g. Head of fibula

The fibularis longus (also known as the peroneus longus) muscle arises at the head of the fibula; the muscle parallels the bone and its tendon passes posterior to the lateral malleolus of the fibula and under the sole of the foot before inserting at the base of the first metatarsal bone. The fibularis longus acts in plantarflexion of the foot (increases the angle between the foot and leg) and also everts the foot (moves the sole away from the median plane). Because

it passes under the longitudinal arch of the foot, it also serves to support the arch. The fibularis brevis (or peroneus brevis) muscle lies deep to the fibularis longus; it originates along the middle part of the fibula and its tendon runs posterior to the lateral malleolus

and inserts at the base of the fifth metatarsal bone. The fibularis brevis is also involved in plantar flexion and eversion of the foot.

132. Deep muscles of the leg, anterior view

a. Tibia

b. Interosseous membrane

c. Inferior extensor retinaculum

d. Medial malleolus

e. Tendon of extensor hallucis longus muscle

f. Tendon of fibularis (peroneus) brevis muscle

g. Lateral malleolus

h. Extensor hallucis longus muscle

i. Fibularis (peroneus) brevis muscle

j. Fibula

The interosseous membrane consists of connective tissue fibers that attach to both the tibia and fibula, stabilizing their positions relative to each other, dividing the anterior from the posterior compartment of the leg, and providing attachment sites for muscles. The extensor hallucis longus muscle arises from the middle half of both the fibula and interosseous membrane; its tendon passes through a channel formed by fibers of the inferior extensor retinaculum passing on either side, then inserts at the base and dorsal surface of the distal phalanx of the great toe. It acts both to dorsiflex the ankle and to extend the great toe. The fibularis brevis muscle arises along the midsection of the fibula and its tendon inserts on the fifth metatarsal bone. The fibularis brevis plantar flexes the ankle and everts the foot.

133. Muscles of the superficial posterior compartment of the leg, posterior view

a. Plantaris muscle

b. Gastrocnemius muscle

c. Aponeurosis of gastrocnemius muscle

d. Lateral malleolus

e. Calcaneal (Achilles) tendon

1. Calcaneus

g. Medial malleolus

h. Soleus muscle

i. Femur

The gastrocnemius muscle has two heads; one arises on the lateral condyle of the femur, the other on the femur above the medial condyle. The deeper soleus muscle originates on the head of the fibula and adjacent areas on the shafts of both the tibia and fibula. The tendon of the gastrocnemius joins with the tendon of the soleus to form the calcaneal tendon that inserts on the large tarsus known as the calcaneus. The calcaneal tendon is commonly known as the Achilles tendon. Both muscles act in plantar flexion of the ankle, and in adduction and inversion of the foot. In addition, the gastrocnemius flexes the knee. The plantaris muscle arises from the lateral supracondylar ridge of the femur; its long tendon inserts on the calcaneal tendon, and it weakly flexes the knee and plantar flexes the ankle.

134. Muscles of the deep posterior view

a. Femur

b. Fibula

c. Flexor hallucis longus

d. Calcaneus

e. Tendon of flexor digitorum longus muscle

f. Tendon of tibialis posterior muscle

posterior compartment of the leg,

g. Medial malleolus

h. Flexor digitorum longus

muscle

i. Tibialis posterior muscle

j. Popliteus muscle

k. Tibia

Deep to the gracilis and soleus muscles, the flexor digitorum longus muscle arises on the tibia, and its tendon passes behind the medial malleolus and under the sole before it divides into four tendons that insert on the inferior surfaces of the distal phalanges of toes 2-5. It flexes the joints of those toes. The flexor hallucis longus arises on the fibula and the interosseous membrane; its tendon passes behind the talus, under the sole of the foot, and inserts on the distal phalanx of the great toe. It flexes the joints of the great toe. The tibialis posterior arises on the interosseous membrane and adjacent areas of the tibia and fibula; its tendon splits into slips that insert on the navicular and second cuneiform tarsals as well as the plantar surfaces of metatarsals 2-4. The tibialis posterior acts to adduct and invert the foot as well as to plantar flex the ankle. The popliteus muscle originates on the lateral condyle of the femur, inserts on the posterior surface of the shaft of the tibia, and medially rotates the tibia at the knee (or laterally rotates the femur).

135. Muscles of the dorsal foot

a. Middle phalanx

b. Distal phalanx

c. Extensor expansion

d. Tendons of extensor digitorum longus muscle

e. Extensor digitorum brevis muscle

1. Calcaneus

g. Extensor hallucis brevis muscle

h. Tendon of extensor hallucis longus muscle

i. Dorsal interosseous muscles

The tendons of the extensor digitorum longus muscle are joined by other extensor tendons to form the extensor expansions that insert on the superior surfaces of the phalanges of toes 2-5 and extend the toes at the interphalangeal joints. The extensor digitorum brevis muscles arise on the calcaneus and insert on the dorsal surfaces of the toes to extend the metatarsophalangeal joints of toes 2-4. The dorsal interosseous muscles arise along the sides of the metatarsal bones, insert on the sides of toes 2-4 and abduct toes 3 and 4 at the metatarsophalangeal joints. The tendon of the extensor hallucis longus muscle inserts on the dorsal surface of the phalanges of the great toe to extend the digit. The extensor hallucis brevis muscle arises on the calcaneus bone, inserts on the proximal phalanx of the great toe, and extends the toe.

136. Plantar muscles of the foot, first and second layers

a. Middle phalanx

b. Flexor digitorum brevis

muscle

c. Tendon of flexor hallucis longus muscle

d. Lumbrical muscles

e. Tendon of flexor digitorum longus muscle

1. Abductor hallucis muscle

g. Calcaneus

h. Quadratus plantae (flexor

accessorius) muscle

i. Abductor digiti minimi muscle

j. Proximal phalanx

k. Distal phalanx

The most superficial of the plantar muscles is the flexor digitorum brevis muscle; it arises on the calcaneus, inserts on the sides of the middle phalanges of toes 2-5 and flexes the toes at the proximal interphalangeal joints. Deep to the flexor digitorum brevis, one can see the tendons of the flexor digitorum longus muscle which insert

on the inferior surface of the distal phalanges to flex toes 2-5 at the interphalangeal joints. The lumbrical muscles arise from the tendons of the flexor digitorum longus and insert on the extensor expansions of toes 2-5 to extend the interphalangeal joints but flex the metatarsophalangeal joints. With an action similar to the lumbricals, the quadratus plantae arises on the calcaneus and inserts on the tendons of the extensor digitorum longus. On the lateral side of the foot, the abductor digiti minimi muscle originates on the calcaneus, inserts on the lateral side of the proximal phalanx of toe 5, and abducts the toe. On the medial side, the tendon of the flexor hallucis longus muscle inserts on the inferior surface of the distal phalanx of the great toe, and flexes the joints of the great toe. The abductor hallucis muscle originates on the calcaneus, inserts on the medial side of the proximal phalanx of the great toe, and abducts the great toe.

SKELETAL SYSTEM (contd)

29. Lumbar vertebra, superior and lateral views

30. Sacrum and coccyx, anterior view

31. Sacrum and coccyx, posterior view

32. Intervertebral discs, lateral and midsagittal views

33. Sternum, anterior view

34. Rib and vertebra, articulated, superior view; rib, posterior view

35. Rib cage, anterior view

36. Pectoral girdle and upper limb, anterior view

37. Scapula, anterior and lateral views

38. Scapula, posterior view

39. Clavicle and related bones, superior view; clavicle, inferior view

40. Humerus, anterior and posterior views

41. Ulna and radius, lateral and anterior views

42. Hand, posterior (dorsal) view

43. Hand, anterior (palmar) view

44. Hip bone, lateral view

45. Pelvis, anterior view

46. Differences between male and female pelvis

47. Lower limb, anterior view

48. Femur and patella, anterior and posterior views

49. Tibia and fibula, anterior and posterior views

50. Bones of the foot, dorsal view

51. Bones of the foot, lateral view

ARTICULATIONS

52. Gomphosis (peg suture)

53. Suture

54. Syndesmosis, posterior view

55. Synchondrosis

56. Symphysis

57. Synovial joint, diagrammatic sagittal section

58. Tendon sheath

59. Bursa

ARTICULATIONS (cont d)

60. Gliding joint

61. Hinge joint

62. Rotating joint

63. Ball and socket joint

64. Condyloid joint

65. Saddle joint

66. Temporomandibular joint, sagittal section

67. Shoulder joint, frontal section

68. Shoulder ligaments, anterior view

69. Elbow joint, sagittal section

70. Elbow ligaments, anterior view

71. Hip joint, frontal section

72. Pelvic ligaments, posterior view

73. Knee joint, anterior view

74. Bent knee joint, anterior view with patella removed

75. Knee joint, sagittal section

76. Ankle joint, posterior view

77. Ankle joint, frontal section

78. Superficial muscles of the body, anterior view

79. Superficial muscles of the body, posterior view

80. Muscle forms: fusiform and flat sheet

81. Muscle forms: pennate, circular, and multicaudal

82. Muscle forms: cylindrical, triangular, quadrilateral, biventral,

multiventral

83. Muscles of facial expression, anterior view

84. Muscles of facial expression, lateral view

85. Superficial muscles of mastication, lateral view

86. Deep muscles of mastication, lateral view

87. Muscles of the neck, anterior view

88. Suprahyoid and infrahyoid muscles of the neck, anterior view

89. Prevertebral region and root of the neck, anterior view

KAPLAN) MEDICAL

90. Muscles of the neck, lateral view

91. Neck, transverse section

92. Ocular muscles, lateral view and superior view

93. Intrinsic muscles of the tongue, sagittal section

94. Extrinsic muscles of the tongue, pharynx and larynx, lateral view

95. Pharynx, posterior view

96. Superficial shoulder muscles, anterior view

97. Muscles of the shoulder, scapula and arm, anterior view

98. Deep muscles of the shoulder and arm, anterior view

99. Muscles with scapular attachments, posterior view

100. Superficial and intermediate muscles of the back, posterior view

101. Deep muscles of the back, posterior view

102. Anterior brachial muscles (flexors), lateral view

103. Posterior brachial muscles (extensors), lateral view

104. Superficial flexor muscles of the forearm, anterior view

105. Superficial extensor muscles of the forearm, lateral view

(hand pronated)

106. Deep flexor muscles of the forearm, anterior view

107. Deep extensor muscles of the forearm, posterior view

108. Transverse sections of the arm

109. Muscles of the hand, posterior (dorsal) view

110. Muscles of the hand, anterior (palmar) view

111. Intercostal muscles, anterior view

112. Diaphragm, anterior view

113. Diaphragm, inferior view

114. Superficial abdominal muscles, anterior view

115. Deep abdominal muscles, anterior view

116. Posterior abdominal wall muscles, anterior view

117. Pelvic diaphragm, superior view

118. Perineal muscles, inferior view

119. Urogenital diaphragm, inferior view

120. Lower limb muscles, anterior view

121. Muscles of the lower limb, posterior view

122. Superficial femoral muscles, anterior view

123. Deep femoral muscles, anterior view

124. Medial femoral muscles, medial view

125. Lateral femoral muscles, lateral view

126. Gluteal muscles, posterior view

127. Posterior femoral muscles, posterior view

128. Posterior thigh and gluteal muscles, deep dissection, posterior view

129. Thigh, transverse section

130. Muscles of the anterior compartment of the leg, anterior view

131. Muscles of the lateral compartment of the leg, lateral view

132. Deep muscles of the leg, anterior view

133. Muscles of the superficial posterior compartment of the leg,

posterior view

134. Muscles of the deep posterior compartment of the leg,

posterior view

135. Muscles of the dorsal foot

136. Plantar muscles of the foot, first and second layers

137. Plantar muscles of the foot, third layer

NERVOUS SYSTEM 138. Nervous system, anterior view

139. Neuron

140. Synapse, cutaway view

141. Central nervous system, sagittal section

142. Brain, lateral view

143. Brain, superior view

144. Brain, inferior view

145. Brain, midsagittal section

146. Brain, frontal section

147. Brain, transverse section

148. Brainstem, posterior view

149. Brainstem, lateral view

150. Limbic system

I(APLA N MEDICAL

NERVOUS SYSTEM (cont'd)

151. Functional areas of the cerebrum

152. Ventricles of the brain

153. Cerebrospinal fluid pathway

154. Meninges of the brain, frontal section

155. Facial nerve and cutaneous branches of the cervical plexus

156. Spinal cord and spinal nerves

157. Branching of a typical spinal nerve, transverse section

158. Spinal membranes and nerve roots

159. Spinal cord, transverse sections

160. Cranial nerves, inferior view

161. Emerging spinal nerves, lateral view

162. Plexuses and thoracic nerves, posterior view

163. Cervical plexus, posterior view

164. Brachial plexus, anterior view

165. Lumbar plexus, anterior view

166. Sacral plexus, posterior view

167. Abdominal sympathetic nerves, anterior view

168. Nerves of the upper limb, anterior view

169. Nerves of the lower limb, posterior view

170. Nerves of the wrist and hand, anterior (palmar) and transverse views

171. Dermatomes, anterior and posterior views

172. Autonomic nervous system, sympathetic division

173. Autonomic nervous system, parasympathetic division

SENSORY SYSTEMS 174. Skin receptors (touch), microscopic view

175. Tongue (taste), superior view

176. Papillae and taste buds of the tongue

177. Nose (smell), midsagittal view

178. Olfactory epithelium

179. Eye and lacrimal apparatus (vision), anterior view

180. Eye (vision), sagittal view

181. Optic retina, ophthalmoscopic and microscopic views

S SORYSYSTEMS front' 182. Auditory system (hearing), anterior view 183. Middle ear, anterior view 184. Inner ear, anterior view 185. Membranous labyrinth of the inner ear, anterior view 186. Cochlea and Organ of Corti, microscopic view

ENDOCRINE SYSTEM 187. Male endocrine system, anterior view 188. Female endocrine system, anterior view 189. Pituitary gland (hypophysis) and pineal body, sagittal section 190. Pituitary gland (hypophysis) hormones and target organs, male 191. Pituitary gland (hypophysis) hormones and target organs, female 192. Thyroid gland, anterior view

193. Parathyroid glands, posterior view

194. Pancreas, anterior view

195. Adrenal gland, anterior and sagittal section views

196. Testis, anterior view

197. Ovary, posterior view and transverse section

198. Placenta, fetal aspect, with diagrammatic transverse section

199. Cardiovascular overview, anterior view

200. Circulation (diagrammatic)

201. Blood cells, microscopic view

202. Anatomical relationships of the heart

203. Heart, anterior view

204. Heart, posterior view

205. Heart, frontal (coronal) section

206. Valves of the heart in ventricular systole, superior view

207. Valves of the heart in ventricular diastole, superior view

208. Conduction system of the heart, frontal (coronal) view

209. Artery and vein structure

KAPLAN) MEDICAL

MIIIIIIIMIIIIIMIMIIIIMIIIIM 210. Arterial system, anterior view

211. Carotid and vertebral arteries, lateral view

212. Branches of the aortic arch, anterior view

213. Brain arteries

214. Middle cerebral artery, lateral view

215. Cerebral arteries, sagittal view

216. Ophthalmic artery, superior view

217. Upper limb arteries, anterior view

218. Lower limb arteries, anterior view

219. Abdominal and thoracic branches of the aorta, anterior view

220. Middle thorax, transverse section viewed from below

221. Digestive system arteries, anterior view

222. Pelvic arteries, male, medial view

223. Pelvic arteries, female, medial view

224. Venous system, anterior view

225. Veins of the head and neck, lateral view

226. Upper limb veins, anterior view

227. Lower limb veins, anterior and posterior view

228. Azygos veins, anterior view

229. Portal system of veins, anterior view

230. Abdominal and thoracic veins of the dorsal wall, anterior view

231. Fetal circulation

LYMPHATIC SYSTEM

232. Overview, anterior view

233. Lymphatic drainage areas, anterior view

234. Lymphatic capillaries, microscopic view

235. Lymphatic drainage at the root of the neck, anterior view

236. Tonsils, sagittal view

237. Waldeyer's ring, anterior view

238. Spleen, anterior view

239. Lymph node, microscopic view of transverse section

240. Intestinal lacteals, anterior and microscopic views

I

1

RESPIRATORY SYSTEM

241. Respiratory overview, anterior view

242. Larynx, trachea and bronchi, anterior view

243. Nasal septum, medial view

244. Nasal cartilages, lateral view

245. Lateral wall of nasal cavity, medial view

246. Nasal conchae, larynx, and sinuses, coronal section

247. Larynx, anterior view

248. Larynx, sagittal section

249. Larynx, posterior view

250. Glottis, superior view

251. Trachea and bronchial tree, anterior and transverse section views

252. Lung lobes and pleura, anterior view

253. Lung hila, medial view

254. Air pathway and alveolus

255. Thorax, transverse section viewed from below

DIGESTIVE SYSTEM

256. Overview, anterior view

257. Overview, lateral view

258. Mouth and oral cavity, anterior view

259. Oral cavity, sagittal section

260. Oral salivary glands, anterior view

261. Salivary glands, lateral view

262. Tooth, sagittal section view

263. Upper teeth, inferior view

264. Esophagus, anterior view

265. Greater omentum, anterior view

266. Stomach, anterior view

267. Stomach, anterior cutaway view

268. Small intestine, anterior view

269. Large intestine, anterior view

270. Liver, anterior view

271. Liver, posterior view

KAPLAN) MEDICAL ....

_I

INTRODUCTION

Illustrator: Stephanie McCann, MA, is an independent medical and scientific illustrator. She received her MA in Medical and Biological Illustration from The Johns Hopkins University, and BA in Fine Arts at the University of California, Santa Cruz. She is currently an instructor at Santa Barbara City College, teaching Biological Illustration (Biology Department) and Adobe Illustrator (Multimedia Arts and Technology Department). Stephanie's studio is located in Santa Barbara, California.

Text: Joanne Kivela Tillotson, PhD, has been teaching undergraduate biology laboratories for over 14 years, the last io of which have been at Purchase College, State University of New York, where she has received the Pedagogy Award for innovative use of technology in the teaching laboratory, and the SUNY Chancellor's Award for Excellence in Teaching. Dr. Tillotson received her BS degree in Biology from the University of Dubuque and PhD in Biochemistry from Michigan State University.

Chief Medical Sonia E. Reichert, MD, previously served as Director Consultant: of Curriculum for Kaplan Medical and is currently

an Internal Medicine Resident at SUNY Downstate at Brooklyn. Dr. Reichert is a regular participant of National Board conferences and has many years of experience in the creation and development of Kaplan Medical's online, print, DVD, and other media related educational tools in the medical and allied health fields. She is the leading national expert in the content, scoring, and structure of medical licensing and allied health exams.

Medical Sailesh Harwani, MD, PhD Proofreader:

KAPLAN) MEDICAL

CONTENTS

BODY ORGANIZATION 1. Anatomical position and terms of direction

2. Anatomical planes of the body

3. Anterior regions of the body

4. Posterior regions of the body

5. Body cavities

6. Skeletal and visceral structures of the head and neck

7. Thoracic, abdominal and pelvic viscera, anterior view

8. Thoracic, abdominal and pelvic viscera, posterior view

9. Thoracic, abdominal and pelvic viscera, right lateral view

10. Thoracic, abdominal and pelvic viscera, left lateral view

INTEGUMENTARY SYSTEM

11. Layers of the skin and associated structures

12. Epidermis

13. Hair

14. Fingernail

SKELETAL SYSTEM

15. Skeleton, anterior view

16. Skeleton, posterior view

17. Anterior view of the skull

18. Skull, lateral view

19. Skull, superior view

20. External surface of the base of the skull

21. Median sagittal section of the skull

22. Right temporal and sphenoid bones

23. Hyoid bone

24. Vertebral column, lateral view

25. Posterior view of the vertebrae

26. Atlas (Ci) and axis (C2), superior view

27. Cervical vertebra, superior and lateral views

28. Thoracic vertebra, superior and lateral views

KAPLA) MEDICAL

Includes

10 INTERACTIVE

COLORING CARDS

a

INTRODUCTION

KAPLAI• MEDICAL

Anatomy Flashcards

Mi CLEARLY LABELED AND DETAILED FULL-COLOR CARDS

ILLUSTRATIONS: STEPHANIE McCANN, MA • TEXT: JOANNE KIVELA TILLOTSON, PhD

CHIEF MEDICAL CONSULTANT: DR. SONIA REICHERT, MD

This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional service. If legal advice or other expert assistance is required, the services of a competent professional should be sought.

© 2009 Kaplan, Inc.

Published by Kaplan Publishing, a division of Kaplan, Inc. 1 Liberty Plaza, 24th Floor New York, NY 10006

All rights reserved. The text of this publication, or any part thereof, may not be reproduced in any manner whatsoever without written permission from the publisher.

Printed in China

January 2009 10 9 8 7 6 5

ISBN-13: 978-1-4 2 77 - 9 694-3

Kaplan Publishing books are available at special quantity discounts to use for sales promotions, employee premiums, or educational purposes. Please email our Special Sales Department to order or for more information at kaplanpublishing@kaplan.com , or write to Kaplan Publishing, 1 Liberty Plaza, 24th Floor, New York, NY 10006.

INTRODUCTION

Kaplan's Anatomy Flashcards is designed to help students of human anatomy learn and memorize the many structures and systems within the human body. Learning human anatomy is a challenge that is best met through a three-part process:

• having clear visualizations of the body's anatomical structures

• gaining a thorough understanding of the relationships between anatomical structures and their functions

• working consistently to review the anatomy in order to internalize anatomical information for future recall

The front of each card contains a vivid and precise full-color illustration. Clear lines and labels on each image indicate the structures to be learned, with the identification key listed on the reverse side. In addition, each card contains a descriptive text, which enhances understanding of the functions and relationships of each structure.

The set is organized and color-coded according to 15 anatomical systems for ease-of-use, and can easily be carried around for learning and review on the go.

As a bonus, this set includes io coloring cards from Kaplan's top-selling Anatomy Coloring Book. Students can color each image and test their knowledge of various anatomical structures for the ultimate in academic retention and recall.

Kaplan's Anatomy Flashcards is the ideal human anatomy study resource for medical and nursing students, healthcare practitioners, and anyone interested in improving their knowledge of human anatomy.

KAPLAN) MEDICAL ,....

INTRODUCTION

Illustrator: Stephanie McCann, MA, is an independent medical and scientific illustrator. She received her MA in Medical and Biological Illustration from The Johns Hopkins University, and BA in Fine Arts at the University of California, Santa Cruz. She is currently an instructor at Santa Barbara City College, teaching Biological Illustration (Biology Department) and

Adobe Illustrator (Multimedia Arts and Technology Department). Stephanie's studio is located in Santa Barbara, California.

Text: Joanne Kivela Tillotson, PhD, has been teaching undergraduate biology laboratories for over 14 years, the last io of which have been at Purchase College, State University of New York, where she has received the Pedagogy Award for innovative use of technology in the teaching laboratory, and the SUNY Chancellor's Award for Excellence in Teaching. Dr. Tillotson received her BS degree in Biology from the University of Dubuque and PhD in Biochemistry from Michigan State University.

Chief Medical Sonia E. Reichert, MD, previously served as Director

Consultant: of Curriculum for Kaplan Medical and is currently an Internal Medicine Resident at SUNY Downstate at Brooklyn. Dr. Reichert is a regular participant of National Board conferences and has many years of experience in the creation and development of Kaplan Medical's online, print, DVD, and other media related educational tools in the medical and allied health fields. She is the leading national expert in the content, scoring, and structure of medical licensing and allied health exams.

Medical Sailesh Harwani, MD, PhD Proofreader:

KAPLAN) MEDICAL

Other Books by Kaplan Medical Anatomy Coloring Book

medEssentials: High-Yield USMLETM Step i Review

USMLETM Step i Qbook, Fourth Edition

USMLETM Step 2 CK Qbook, Fourth Edition

USMLETM Step 3 Qbook, Fourth Edition

USMLETM Medical Ethics: The loo Cases You Are Most Likely to See on the Exam

USMLETM Step 2 CS: Complex Cases

USMLETM Flashcards: The 200 Diagnostic Tests You Need to Know for the Exam

USMLETM Physical Findings Flashcards: The 200 Questions You Are Most Likely to See on the Exam

USMLETM Pharmacology & Treatment Flashcards: The 200 Questions You Are Most Likely to See on the Exam

•

1. Anatomical position and terms of direction

2. Anatomical planes of the body

3. Anterior regions of the body

4. Posterior regions of the body

5. Body cavities

6. Skeletal and visceral structures of the head and neck

7. Thoracic, abdominal and pelvic viscera, anterior view

8. Thoracic, abdominal and pelvic viscera, posterior view

9. Thoracic, abdominal and pelvic viscera, right lateral view

10. Thoracic, abdominal and pelvic viscera, left lateral view

INTEGUMENTARY SYSTEM

11. Layers of the skin and associated structures

12. Epidermis

13. Hair

14. Fingernail

SKELETAL SYSTEM

15. Skeleton, anterior view

16. Skeleton, posterior view

17. Anterior view of the skull

18. Skull, lateral view

19. Skull, superior view

20. External surface of the base of the skull

21. Median sagittal section of the skull

22. Right temporal and sphenoid bones

23. Hyoid bone

24. Vertebral column, lateral view

25. Posterior view of the vertebrae

26. Atlas (Ci) and axis (C2), superior view

27. Cervical vertebra, superior and lateral views

28. Thoracic vertebra, superior and lateral views

KAPLA_t0 MEDICAL

SKELETAL SYSTEM (coati)

29. Lumbar vertebra, superior and lateral views

30. Sacrum and coccyx, anterior view

31. Sacrum and coccyx, posterior view

32. Intervertebral discs, lateral and midsagittal views

33. Sternum, anterior view

34. Rib and vertebra, articulated, superior view; rib, posterior view

35. Rib cage, anterior view

36. Pectoral girdle and upper limb, anterior view

37. Scapula, anterior and lateral views

38. Scapula, posterior view

39. Clavicle and related bones, superior view; clavicle, inferior view

40. Humerus, anterior and posterior views

41. Ulna and radius, lateral and anterior views

42. Hand, posterior (dorsal) view

43. Hand, anterior (palmar) view

44. Hip bone, lateral view

45. Pelvis, anterior view

46. Differences between male and female pelvis

47. Lower limb, anterior view

48. Femur and patella, anterior and posterior views

49. Tibia and fibula, anterior and posterior views

50. Bones of the foot, dorsal view

51. Bones of the foot, lateral view

ARTICULATIONS

52. Gomphosis (peg suture)

53. Suture

54. Syndesmosis, posterior view

55. Synchondrosis

56. Symphysis

57. Synovial joint, diagrammatic sagittal section

58. Tendon sheath

59. Bursa

•

DIGESTIVE SYSTEM (cont'd)

272. Gall bladder, pancreas and duodenum, anterior view

273. Gall bladder, pancreas and duodenum, anterior cutaway view

274. Rectum, coronal section view

275. Abdomen, transverse section at T12, seen from below

276. Abdomen, transverse section at Li, seen from below

URINARY SYSTEM

277. Overview, female urinary system, anterior view

278. Anatomical relationships of the urinary system, anterior view

279. Overview, male urinary system, anterior view

280. Overview, male urinary system, viewed from the left

281. Kidney, anterior view

282. Kidney, frontal section view

283. Kidney and renal artery, frontal section view

284. Female urinary bladder, frontal section view

285. Nephron of the kidney, microscopic view

REPRODUCTIVE SYSTEM

286. Overview male reproductive system, anterior view

287. Male pelvis, anterolateral view

288. Male reproductive system, sagittal section view

289. Testes, anterior view

290. Seminal vesicles, prostate gland and seminiferous tubules,

posterior view

291. Penis, ventral and cross section views

292. Spermatogenesis, microscopic view

293. Overview female reproductive system, anterior view

294. Female pelvis, anterior view

295. Female reproductive system, sagittal section view

296. Ovary, frontal section view

297. Female reproductive system, menstrual cycle

298. Uterus, ovaries and vagina, frontal section, posterior view

REPRODUCTIVE SYSTEM (cont'd)

299. Mammary gland and lymphatic drainage, anterior view

300. Female external genitalia, inferior view

COLORING CARDS

301. Regions of the abdomen, anterior view 302. Skeletal system, anterior view

303. Nervous system, posterier view

304. Lymphatic system

305. Muscular system

306. Digestive system

307. Cardiovascular system: arteries

308. Skeletal system: hand, posterior (dorsal) view

309. Nervous system: brain, midsagittal section

310. Respiratory system

l'1_).Ati MEDICAL

This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional service. If legal advice or other expert assistance is required, the services of a competent professional should be sought.

© 2009 Kaplan, Inc.

Published by Kaplan Publishing, a division of Kaplan, Inc. 1 Liberty Plaza, 24th Floor New York, NY l0006

All rights reserved. The text of this publication, or any part thereof, may not be reproduced in any manner whatsoever without written permission from the publisher.

Printed in China

January 2009 10 9 8 7 6 5

ISBN-13: 978-1-4277-9694-3

Kaplan Publishing books are available at special quantity discounts to use for sales promotions, employee premiums, or educational purposes. Please email our Special Sales Department to order or for more information at kaplanpublishing@kaplan.com , or write to Kaplan Publishing, i Liberty Plaza, 24th Floor, New York, NY 101306.

DMIODUCTION

Illustrator: Stephanie McCann, MA, is an independent medical and scientific illustrator. She received her MA in Medical and Biological Illustration from The Johns Hopkins University, and BA in Fine Arts at the University of California, Santa Cruz. She is currently an instructor at Santa Barbara City College, teaching Biological Illustration (Biology Department) and Adobe Illustrator (Multimedia Arts and Technology Department). Stephanie's studio is located in Santa Barbara, California.

Text: Joanne Kivela Tillotson, PhD, has been teaching undergraduate biology laboratories for over 14 years, the last io of which have been at Purchase College, State University of New York, where she has received the Pedagogy Award for innovative use of technology in the teaching laboratory, and the SUNY Chancellor's Award for Excellence in Teaching. Dr. Tillotson received her BS degree in Biology from the University of Dubuque and PhD in Biochemistry from Michigan State University.

Chief Medical Sonia E. Reichert, MD, previously served as Director Consultant: of Curriculum for Kaplan Medical and is currently

an Internal Medicine Resident at SUNY Downstate at Brooklyn. Dr. Reichert is a regular participant of National Board conferences and has many years of experience in the creation and development of Kaplan Medical's online, print, DVD, and other media related educational tools in the medical and allied health fields. She is the leading national expert in the content, scoring, and structure of medical licensing and allied health exams.

Medical Sailesh Harwani, MD, PhD Proofreader:

IIA P LAN) MEDICAL

A

Other Books by Kaplan Medical Anatomy Coloring Book

medEssentials: Nigh•Yield USMLETM Step: Review

USMLETM Step i Qbook, Fourth Edition

USMLETM Step 2 CK Qbook, Fourth Edition

USMLETM Step 3 Qbook, Fourth Edition

USMLETM Medical Ethics: The zoo Cases You Are Most Likely to See on the Exam

USMLETM Step 2 CS: Complex Cases

USMLETM Flashcards: The 200 Diagnostic Tests You Need to Know for the Exam

USMLETM Physical Findings Flashcards: The zoo Questions You Are Most Likely to See on the Exam

USMLETM Pharmacology & Treatment Flashcards: The zoo Questions You Are Most Likely to See on the Exam

Kaplan's Anatomy flashcards is designed to help students of human anatomy learn and memorize the many structures and systems within the human body. Learning human anatomy is a challenge that is best met through a three-part process:

• having clear visualizations of the body's anatomical structures

• gaining a thorough understanding of the relationships between anatomical structures and their functions

• working consistently to review the anatomy in order to internalize anatomical information for future recall

The front of each card contains a vivid and precise full-color illustration. Clear lines and labels on each image indicate the structures to be learned, with the identification key listed on the reverse side. In addition, each card contains a descriptive text, which enhances understanding of the functions and relationships of each structure.

The set is organized and color-coded according to 15 anatomical systems for ease-of-use, and can easily be carried around for learning and review on the go.

As a bonus, this set includes io coloring cards from Kaplan's top-selling Anatomy Coloring Book. Students can color each image and test their knowledge of various anatomical structures for the ultimate in academic retention and recall.

Kaplan's Anatomy Flashcards is the ideal human anatomy study resource for medical and nursing students, healthcare practitioners, and anyone interested in improving their knowledge of human anatomy.

!CAPLAN) MEDICAL

CONTENTS

BODYORGANIZATION 1. Anatomical position and terms of direction 2. Anatomical planes of the body 3. Anterior regions of the body 4. Posterior regions of the body 5. Body cavities 6. Skeletal and visceral structures of the head and neck 7. Thoracic, abdominal and pelvic viscera, anterior view 8. Thoracic, abdominal and pelvic viscera, posterior view 9. Thoracic, abdominal and pelvic viscera, right lateral view

10. Thoracic, abdominal and pelvic viscera, left lateral view

INTEGUMENTARYSYSTEM 11. Layers of the skin and associated structures 12. Epidermis 13. Hair 14. Fingernail

SKELETAL SYSTEM 15. Skeleton, anterior view 16. Skeleton, posterior view 17. Anterior view of the skull 18. Skull, lateral view 19. Skull, superior view 20. External surface of the base of the skull 21. Median sagittal section of the skull 22. Right temporal and sphenoid bones 23. Hyoid bone 24. Vertebral column, lateral view 25. Posterior view of the vertebrae 26. Atlas (Ci) and axis (C2), superior view 27. Cervical vertebra, superior and lateral views 28. Thoracic vertebra, superior and lateral views

!CAPLAN) MEDICAL

r SKELETAL SYSTEM (cont'd)

29. Lumbar vertebra, superior and lateral views 30. Sacrum and coccyx, anterior view 31. Sacrum and coccyx, posterior view 32. Intervertebral discs, lateral and midsagittal views 33. Sternum, anterior view 34. Rib and vertebra, articulated, superior view; rib, posterior view 35. Rib cage, anterior view 36. Pectoral girdle and upper limb, anterior view 37. Scapula, anterior and lateral views 38. Scapula, posterior view 39. Clavicle and related bones, superior view; clavicle, inferior view 40. Humerus, anterior and posterior views 41. Ulna and radius, lateral and anterior views 42. Hand, posterior (dorsal) view 43. Hand, anterior (palmar) view 44. Hip bone, lateral view 45. Pelvis, anterior view 46. Differences between male and female pelvis 47. Lower limb, anterior view 48. Femur and patella, anterior and posterior views 49. Tibia and Fibula, anterior and posterior views 50. Bones of the foot, dorsal view 51. Bones of the foot, lateral view

ARTICULATIONS

52. Gomphosis (peg suture) 53. Suture 54. Syndesmosis, posterior view 55. Synchondrosis 56. Symphysis 57. Synovial joint, diagrammatic sagittal section 58. Tendon sheath 59. Bursa

...

52. Gomphosis (peg suture)

a. Tooth

b. Alveolar socket

c. Enamel

d. Dentin

e. Pulp

f. Gingiva

g. Alveolar ridge

h. Periodontal ligaments

A gomphosis is a fibrous synarthrotic (immovable) joint holding a tooth in its alveolar socket in the maxilla or mandible. The bulk of the tooth is

composed of dentin, a mineralized matrix secreted by cells found in the

pulp cavity. The exposed portion of the tooth is covered by a crystalline

calcium phosphate layer called enamel—the hardest substance in the

human body. The root of the tooth is bound in place by the periodontal

ligament; it is composed of collagen fibers extending from the dentin

of the tooth to the bone surrounding the root of the tooth. A bony

alveolar ridge forms the deep socket or alveolus where the peg-like

root of the tooth is inserted. Superficial to the bone is the gingiva,

mucosal tissue tightly bound to the bone surrounding the teeth; it

provides a smooth surface to reduce friction with food.

53. Suture

a. Sagittal suture

A suture is a fibrous synarthrotic (immovable) joint located between

the bones of the skull, in order to form a protective case for the brain

and sensory organs of the head. Cranial sutures include the sagittal suture shown here, which connects the two parietal bones and extends

between the anterior coronal suture and the posterior lambdoid

suture. Further attachment between bones at the suture is provided

by collagen fibers that bind the bones in a firm but slightly flexible

manner. The bone edges at the sutures are interlocking in adults,

although they are slightly separated and are only connected by fibrous

connective tissue during development to allow both more flexibility

of the skull during birth and room for growth as the brain increases in

size during the early postnatal period.