Appendicular Skeleton

Prof. Abdulameer Al-Nuaimia.alnuaimi@sheffield.ac.uk abdulameerh@yahoo.com

Hi Prof, It is great to hear from you, I really enjoyed yourteaching last year. You taught me the hardest subject I haveencountered so far in a manner that I understood and couldremember. I hope you are enjoying your new job in Jordon.Are you still teaching anatomy? Many thanks for yourteaching and best of luck in JordonSam Allison

Appendicular Skeleton

Each upper limb skeletonconsists of 32 bones,which form two distinctregions:

➢The pectoral girdle.

▪ Clavicle.

▪ Scapula.

➢The free upper limb.

▪Humerus.

▪Ulna

▪ Radius.

▪Hand.

The pectoral girdle

The clavicle is theanterior bone and thescapula is the posteriorbone.

Clavicle

• S - shaped bone.

• Lies horizontally across the anterior part of the thoraxsuperior to the first rib.

• The medial half of the clavicle is convex anteriorlyand the lateral half is concave anteriorly.

• The medial end of the clavicle, called the sternal end,is rounded and articulates with the manubrium of thesternum to form the sternoclavicular joint .

• The broad, flat, lateral end, the acromial end ,articulates with the acromion of the scapula at theacromioclavicular joint.

• The superior surface of the clavile (smooth), whilethe inferior surface (rough).

Clavicle

Scapula• scapula or shoulder blade, is a large, triangular, flat bone

with a ridge on its posterior surface.

• The scapula occupies the superior part of the posteriorthorax between the levels of the second and seventh ribs afew finger breadths lateral to the vertebral column.

• A prominent ridge called the spine across the posteriorsurface of the scapula.

• The lateral end of the spine projects as a flattened,expanded process called the Acromion

• Inferior to the acromion is a shallow depression, theglenoid cavity, that accepts the head of the humerus toform the glenohumeral joint, or shoulder joint.

• The thin edge of the scapula closer to the vertebral columnis called the medial (vertebral) border.

Scapula

Scapula

• The thick edge of the scapula closer to the arm is called thelateral (axillary) border.

• The medial and lateral borders join at the inferior angle.

• The superior edge of the scapula, called the superiorborder, joins the vertebral border at the superior angle.

• The scapular notch is a prominent indentation along thesuperior border.

• At the lateral end of the superior border of the scapula isthe coracoid process.

• Superior and inferior to the spine are two fossae: thesupraspinous fossa and the infraspinous fossa.

• On the anterior surface is a slightly hollowed-out areacalled the subscapular fossa.

Scapula

Humerus

The humerus or armbone, is the longest andlargest bone of the upperlimb.

It has a ball-like proximalend with two prominentprojections of bone at thebase of the ball, acylindrical, tubular shaftthat makes up themajority of its length, andan expanded flatteneddistal end.

Humerus• It articulates proximally with the scapula and distally with

both the ulna and the radius to form the elbow joint.

• The proximal end of the humerus features a rounded headthat articulates with the glenoid cavity of the scapula toform the glenohumeral (shoulder) joint.

• Distal to the head is the anatomical neck, which is visible asan oblique groove.

• The greater tubercle is a lateral projection distal to theanatomical neck.

• The lesser tubercle projects anteriorly.

• Between both tubercles runs an intertubercular sulcus.

• The surgical necek is a constriction in the humerus justdistal to the tuercles. It is a common fracture site of thehumerus (in contct posteriorly with the axillary nerve)

Humerus

Humerus

Laterally, at the middleportion of the shaft, thereis a roughened, V-shapedarea called the deltoidtuberosity.

This area serves as a pointof attachment for thetendon of the deltoidmuscle.

The radial groove runsalong the posteriorsurface of the humerus.

This groove contains theradial nerve

Humerus

at the distal end of the humerus, rounded knob on the lateralaspect of the bone that articulates with the head of theradius (capitulum).

The radial fossa is an anterior depression above thecapitulum that articulates with the head of the radius whenthe forearm is flexed.

The trochlea, located medial to the capitulum, that articulateswith the ulna.

The coronoid fossa, anterior depression that receives thecoronoid process of the ulna when the forearm is flexed.

The olecranon fossa is the large posterior depression thatreceives the olecranon of the ulna when the forearm isextended.

Lower end of humerus

Humerus

The medial epicondyleand lateral epicondyle arerough projections oneither side of the distalend of the humerus towhich the tendons ofmost muscles of theforearm are attached.

The ulnar nerve passesposterior to the medialepicondyle in contact with

The bone. Fractured hum.

might injure these nerves

Lat Epicond

Med Epicond

Ventral surface Dorsal surface

Ulna• The ulna is located on

the medial aspect of theforearm and is longerthan the radius.

• The ulna is thick andnotched at its proximalend, and its widetriangular shaft tapersto become more narrowand cylindrical distally.

• At the proximal end ofthe ulna is theolecranon, which formsthe prominence of theelbow.

Ulna

• The coronoid process an anterior projection distal to alarge notch, the trochlear notch.

• The trochlear notch on the anterior side of the olecranon,receives the trochlea of the humerus to form part of theelbow joint.

• The radial notch is a depression that is lateral and inferiorto the trochlear notch and articulates with the head of theradius.

• Just inferior to the coronoid process is the ulnartuberosity.

• The distal end of the ulna consists of a head that isseparated from the wrist by a disc of fibrocartilage.

• A styloid process is located on the posterior side of theulna’s distal end.

Upper end of ulna

Radius• The radius, the shorter of the two forearm bones, is

located on the lateral aspect of the forearm.

• In contrast to the ulna, the radius is narrow at its proximalend and widens at its distal end.

• The proximal end of the radius has a disc-shaped head thatarticulates with the capitulum of the humerus and theradial notch of the ulna.

• Inferior to the head is the constricted neck.

• A roughened area inferior to the neck on the anteromedialside, called the radial tuberosity, is a point of attachmentfor the tendon of the biceps brachii muscle.

• The shaft of the radius widens distally to form a styloidprocess on the lateral side.

Radius and Ulna

Radius

• The ulna and radius articulate with the humerus atthe elbow joint.

• The elbow articulation occurs in two places: wherethe head of the radius articulates with the capitulumof the humerus, and where the trochlear notch ofthe ulna receives the trochlea of the humerus.

• The ulna and the radius connect with one another atthree sites. First, a broad, flat, fibrous connectivetissue called the interosseous membrane, joins theshafts of the two bones.

• The ulna and radius articulate at their proximal anddistal ends.

Radius

• Proximally, the head of the radius articulates with theulna’s radial notch, a depression that is lateral and inferiorto the trochlear notch. This articulation is the proximalradioulnar joint.

• Distally, the head of the ulna articulates with the ulnarnotch of the radius. This articulation is the distal radioulnarjoint.

• Finally, the distal end of the radius articulates with threebones of the wrist—the lunate, the scaphoid, and thetriquetrum to form the radiocarpal (wrist) joint.

Upper and lower ends of Radius and Ulna

Bones of the hand

Carpals. (8), Metacarpals. (5), Phalanges. (14)

Carpals

• The carpus (wrist) is the proximal region of the hand andconsists of eight small bones, the carpals, joined to oneanother by ligaments.

• Articulations between carpal bones are called intercarpaljoints.

• The carpals are arranged in two transverse rows of fourbones each.

Metacarpals

• The metacarpus or palm, is the intermediate region of thehand; it consists of five bones called metacarpals.

• Each metacarpal bone consists of a proximal base, anintermediate shaft, and a distal head.

• The metacarpal bones are numbered I to V (1-5), startingwith the thumb, from lateral to medial.

• The bases articulate with the distal row of carpal bones toform the carpometacarpal joints.

• The heads articulate with the proximal phalanges to formthe metacarpophalangeal (MP) joints.

Phalanges

• The phalanges or bones of the digits, make up the distalregion of the hand.

• There are 14 phalanges in the five digits of each hand.

• Like the metacarpals, the digits are numbered I to V (or 1–5), beginning with the thumb from lateral to medial.

• Each phalanx consists of a proximal base, an intermediateshaft, and a distal head.

• The thumb has two phalanges, and there are threephalanges in each of the other four digits.

• In order from the thumb, these other four digits arecommonly referred to as the index finger, middle finger,ring finger, and little finger.

Bones of the Hand

Lower LimbEach lower limb skeleton consists of 31 bones, which

form two distinct regions:

➢ The pelvic girdle.

▪ consists of the two hip bones, also called coxal(pelvic) bones.

• The hip bones unite anteriorly at a joint called thepubic symphysis.

• They unite posteriorly with the sacrum at thesacroiliac joints.

• The complete cylinder composed of the hip bones,pubic symphysis, and sacrum forms a deep, basin likestructure called the bony pelvis.

• pelvis also connects the bones of the free lower limbsto the axial.

Hip bones are parts of the pelvis

Each of the two hip bones of a newborn consists of three

bones separated by cartilage: a superior ilium, an inferior

anterior pubis, and an inferior posterior ischium. By age 23,

the three separate bones fuse together.

The free lower limb (extremity)

has 30 bones in four locations:

the femur in the thigh;

the patella (knee cap);

the tibia and fibula in the leg;

the 7 tarsal bones in the

tarsus (ankle), the 5 metatarsal

bones in the metatarsus, and

the 14 phalanges (bones

of the digits) in the foot.

Ilium

• The ilium is the largest of the three components ofthe hip bone.

• It is thick near the hip joint and expands into a largecurved plate of bone superiorly.

• A superior ala (wing) and an inferior body comprisethe ilium. The body is one of the components of theacetabulum, the socket for the head of the femur.

• The superior border of the ilium, the iliac crest, endsanteriorly in a blunt anterior superior iliac spine.

• The medial surface of the ilium contains the iliacfossa, a concavity where the tendon of the iliacusmuscle attaches.

Parts of the Hip bone

Ischium

• The ischium the inferior and posterior portion of thehip bone, is situated between the body of the iliumand the inferior ramus of the pubis.

• The ischium is a arched or U-shaped structure, withits concave, notched margin contributing to theposterior two thirds of the obturator foramen (thelarge hole on the hip bone).

• The ischium is comprised of a superior body and aninferior ramus.

Hip bone

PubisThe pubis is the inferior, anterior portion of the hip bone and, like the ischium, has the form of a sideways arch or a U-shape. It composed of a superior ramus, an inferior ramus, and a body between the rami. The anterior, superior border of the body is the pubic crest, and at its lateral end is a projection called the pubic tubercle.

The pubic symphysis is the joint between the pubes of thetwo hip bones.

The acetabulum is a deep fossa formed by the ilium, ischium, and pubis. It functions as the socket that contains the rounded head of the femur. Together, the acetabulum and the femoral head form the hip (coxal) joint.

Hip bone

Bony PelvisThe portion of the bony pelvis superior to the pelvic brim isthe false (greater) pelvis.

It is bordered by the lumbar vertebrae posteriorly, the upperportions of the hip bones laterally, and the abdominal wallanteriorly.

It contains the superior portion of the urinary bladder andlower intestines in both genders and the uterus, ovaries, anduterine tubes of the female, The portion of the bony pelvisinferior to the pelvic brim is the true (lesser) pelvis.

It is bounded by the sacrum and coccyx posteriorly, inferiorportions of the ilium and ischium laterally, and the pubicbones anteriorly. It contains the rectum and urinary bladderin both genders, the vagina and cervix of the uterus infemales, and the prostate in males.

Pelvis

False Pelvis True pelvis

Bony PelvisThe superior opening of the true pelvis, bordered by thepelvic brim, is called the pelvic inlet;

The inferior opening of the true pelvis is the pelvic outlet.

difference between male and female pelves

Oval and Wider transversely Heart shape

Round Oval

Shallow Cylindrical Long Funnel

Rounded Angular

FemurThe femur, or thigh bone,is the longest, heaviest,and strongest bone in thebody.

Its proximal end articulates with the acetabulum of the hip bone.

Its distal end articulateswith the tibia and patella.

The shaft of the femurdirected medially and, as aresult, the knee joints arecloser to the midline thanthe hip joints.

Femur

The proximal end of thefemur consists of arounded head thatarticulates with theacetabulum of the hipbone to form the hipjoint.

The head contains a small, central depression called the fovea capitis.

The neck of the femur is aconstricted region distal tothe head.

Femur

• The greater trochanter and lesser trochanter areprojections that serve as points of attachment for thetendons of some of the thigh and buttock muscles.

• The greater trochanter is the prominence felt and It is alandmark commonly used to locate the site forintramuscular injections into the lateral surface of thethigh. The lesser trochanter is inferior and medial to thegreater trochanter.

• Between the anterior surfaces of the trochanters is anarrow intertrochanteric line .

• A ridge called the intertrochanteric crest appears betweenthe posterior surfaces of the greater trochanter and lessertrochanter.

Femur

Femur

• Inferior to the intertrochanteric crest on the posteriorsurface of the body of the femur is a vertical ridge calledthe gluteal tuberosity. It blends into another vertical ridgecalled the linea aspera .

• The expanded distal end of the femur includes the medialcondyle and the lateral condyle. These articulate with themedial and lateral condyles of the tibia.

• A depressed area between the condyles on the posteriorsurface is called the intercondylar fossa.

• Superior to the condyles are the medial epicondyle andthe lateral epicondyle.

Femur

The patellar surfaceis located betweenthe condyles on theanterior surface.

Just superior to themedial epicondyleis the adductortubercle, aroughenedprojection that is asite of attachmentfor the adductormagnus muscle.

Patella

• The patella (kneecap), is a small, triangular bone.

• located anterior to the knee joint.

• It is a sesamoid bone.

• The broad proximal end of the patella is called thebase.

• The pointed distal end is the apex.

• The posterior surface contains two articular facets.

Patella

Tibia• The tibia is the larger, medial, weight-bearing bone of the

leg.

• The tibia is the second longest bone of the body.

• The tibia articulates at its proximal end with the femurand fibula and at its distal end with the fibula and thetalus bone of the ankle.

• The tibia and fibula, are connected by an interosseousmembrane.

• The proximal end of the tibia is expanded into a lateralcondyle, medial condyle and Intercondylar Eminence

• Tibial condyles articulate with the condyles of the femurforming knee joint. The inferior surface of the lateralcondyle articulates with the head of the fibula.

Tibia

• The tibial tuberosity on the anterior surface is a point ofattachment for the patellar ligament.

• Inferior to and continuous with the tibial tuberosity is asharp ridge that can be felt below the skin and is known asthe anterior border.

• The medial surface of the distal end of the tibia forms themedial malleolus. This structure articulates with the talusof the ankle and forms the prominence that can be felt onthe medial surface of the ankle.

• Laterally, the fibular notch articulates with the distal end ofthe fibula to form the distal tibiofibular joint.

Tibia and Fibula

Fibularnotch

Fibula• The fibula is a slender bone that is slightly expanded at

both ends.

• The fibula is parallel and lateral to the tibia, but isconsiderably smaller.

• Unlike the tibia, the fibula does not articulate with thefemur and is non-weight-bearing, but it does help stabilizethe ankle joint.

• The head of the fibula, the proximal end, articulates withthe inferior surface of the lateral condyle of the tibiabelow the level of the knee joint to form the proximaltibiofibular joint.

• The distal end has a projection called the lateral malleolusthat articulates with the talus of the ankle. This forms theprominence on the lateral surface of the ankle.

Tibia and Fibula

Fibula

The fibula also articulateswith the tibia at thefibular notch to form thedistal tibiofibular joint.

The fibula is a commonsource for bone grafting

Tibia

Tarsals

• The tarsus (ankle) is the proximal region of the foot andconsists of seven tarsal bones.

• Joints between tarsal bones are called intertarsal joints.

• The tarsal bones include the talus and calcaneus, locatedin the posterior part of the foot. The calcaneus is thelargest and strongest tarsal bone.

• The anterior tarsal bones are:

• Navicular bone.

• Three cuneiform bones called the lateral, intermediateand medial.

• Cuboid.

Foot

Metatarsals

• The metatarsus is the intermediate region of the foot andconsists of five metatarsal bones

• They are convex dorsally and concave on their plantarsurfaces.

• Like the metacarpals of the palm, each metatarsal consistsof a proximal base, an intermediate shaft, and a distalhead.

• The metatarsals articulate proximally with the first,second, and third cuneiform bones and with the cuboid toform the tarsometatarsal joints.

• Distally, they articulate with the proximal row of phalangesto form the metatarsophalangeal joints.

• The first metatarsal is thicker than the others because itbears more weight.

Foot

Phalanges

• The phalanges comprise the distal component of the foot.

• The toes are numbered I to V (or 1–5) beginning with thebig toe (great toe) medially.

• Each phalanx consists of a proximal base, an intermediate,shaft, and a distal head.

• The great or big toe has two large, thick phalanges calledproximal and distal phalanges.

• The other four toes each have three phalanges proximal,middle, and distal.

• Joints between phalanges of the foot, like those of thehand, are called interphalangeal joints.

Foot

Sun Set Malaysia16 Feb. 2015

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