The Appendicular Skeleton

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The Appendicular Skeleton. The Appendicular Skeleton. 126 bones Limbs (appendages) Pectoral girdle (attaches arm to the axial skeleton) Pelvic girdle (attaches leg to the axial skeleton). The Pectoral (Shoulder) Girdle. Composed of two bones Clavicle - collarbone - PowerPoint PPT Presentation

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Nerve activates contractionCopyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University
ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY
The Appendicular Skeleton
The Appendicular Skeleton
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pectoral (Shoulder) Girdle
Composed of two bones
The Pectoral (Shoulder) Girdle
These bones are very light and allow the upper limb to have exceptionally free movement because:
Each pectoral girdle attaches to axial skeleton at only 1 point = sternoclavicular joint
The loose attachment of the scapula allows it to slide back & forth against the thorax
The glenoid cavity is shallow & the shoulder joint is poorly reinforced by ligaments
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Bones of the Shoulder Girdle
Figure 5.20a–b
The Pectoral (Shoulder) Girdle
Consists of 2 bones
Clavicle (collar bone) = slender, double curved bone
Attaches to manubrium of the sternum medially & to the scapula laterally
Acts as a brace to hold the arm away from the thorax & helps prevent shoulder dislocation
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pectoral (Shoulder) Girdle
Scapula (shoulder blade) = triangular & flare when we move our arms posteriorly (“wings”)
Not directly attached to axial skeleton; held in place by trunk muscles
Flattened body w/ 2 processes:
Acromion process
Coracoid process
The Pectoral (Shoulder) Girdle
Acromion process = the enlarged end of the spine of the scapula
Connects w/ the clavicle @ the acromioclavicular joint
Coracoid process = beaklike
Points over the shoulder & anchors some of the arm muscles
Suprascapular notch serves as a nerve passageway
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pectoral (Shoulder) Girdle
Superior
Bones of the Shoulder Girdle
Figure 5.20c–d
Bones of the Upper Limb (30)
The arm is formed by a single bone
Humerus
Figure 5.21a–b
Bones of the Upper Limb (30)
Opposite of the head – 2 bony processes = greater & lesser tubercles, sites of muscle attachment
Midpoint of shaft – deltoid tuberosity where the deltoid m. attaches
Figure 5.21a–b
Bones of the Upper Limb (30)
Radial groove runs obliquely down the posterior shaft
Distal end – medial trochlea (looks like a spool) & lateral ball-like capitulum – both articulate w/ bones of forearm
Figure 5.21a–b
Bones of the Upper Limb (30)
Above the trochlea anteriorly is a depression – coronoid fossa
On posterior surface is the olecranon fossa
Both are flanked by medial & lateral epicondyles
Figure 5.21a–b
Bones of the Upper Limb
The forearm consists of the radius and the ulna.
Radius is lateral when the arm is in the anatomical position (on the thumb side) & the ulna is medial
When the hand is rotated, the distal end of the radius crosses over & ends up medial to the ulna.
Figure 5.21c
Bones of the Upper Limb
Radius & ulna articulate @ small radioulnar joints
They are connected along their entire length by a flexible interosseous membrane
Both have a styloid process @ their distal end
Figure 5.21c
Bones of the Upper Limb
Disc-shaped radial head forms a joint w/ the capitulum of the humerus.
Below the head is the radial tuberosity where tendon of biceps m. attaches.
Figure 5.21c
Bones of the Upper Limb
On the ulna’s proximal end are the anterior coronoid process & the posterior olecranon process, which are separated by the trochlear notch.
These 2 processes grip the trochlea of the humerus in a pliers-like joint.
Figure 5.21c
Bones of the Upper Limb
Hand consists of carpals, metacarpals & phalanges
8 carpals arranged in 2 irregular rows of 4 bones each form the part of the hand called the carpus (wrist)
Bound together by ligaments that restrict movements between them.
Figure 5.22
Bones of the Upper Limb
Metacarpals form the palm
Numbered 1 to 5 from the thumb to the pinky
Clenched fist – heads of the metacarpals = knuckles
Phalanges (14) are the finger bones (3 in each finger & 2 in the thumb)
Figure 5.22
Bones of the Upper Limb
Carpals starting Left to Right (pinky to thumb - both rows):
Joe took a Hamate and hit poor Pete in the Capitate, breaking it into a Trapezoid and Trapezium. He did it b/c he was Pisiform(d) Triquetral times. The Judge said he was Lunate and sent him to the Scaphoid.
Figure 5.22
The Bony Pelvis vs. the Pelvic Girdle
Bony Pelvis
Composed of:
Pelvic Girdle
Ilium
Ischium
The Bony Pelvis
The Pelvic Girdle: Right Coxal Bone
Figure 5.23b
The Pelvic Girdle
Coxae are large, heavy & attached securely to the axial skeleton.
Sockets that receive the femur are deep & heavily reinforced w/ ligaments.
Function = bearing weight; total wt. of upper body rests on pelvis.
Reproductive organs, bladder & part of large intestine lie within & are protected by pelvis.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pelvic Girdle
Each coxa is formed by the fusion of 3 bones:
Ilium (Large flaring bone - forms most of the coxa)
Connects posteriorly w/ sacrum @ the sacroiliac joint.
Alae - winglike portions of the ilia.
Iliac crest – upper edge of alae that ends anteriorly in the anterior superior iliac spine & posteriorly in the posterior superior iliac spine w/ small inferior spines located below these.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pelvic Girdle
Ischial tuberosity, a roughened area, receives body wt. when sitting.
Ischial spine, superior to the tuberosity, narrows the outlet through which the baby passes during childbirth.
Greater sciatic notch allows blood vessels & the large sciatic nerve to pass from the pelvis posteriorly into the thigh.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pelvic Girdle
Most anterior part of the coxa.
Fusion of the rami of the pubis anteriorly & the ischium posteriorly forms a bar of bone enclosing the obturator foramen, an opening through which blood vessels & nerves pass into the anterior part of the thigh.
Pubic bones fuse anteriorly to form a cartilaginous joint called the pubic symphysis.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Pelvic Girdle
The ilium, ischium, & pubis fuse @ the deep socket called the acetabulum (“vinegar cup”); it receives the head of the femur.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Bony Pelvis
Bony pelvis is divided into 2 regions:
False pelvis, superior to the true pelvis, is the area medial to the flaring portions of the ilia.
True pelvis lies inferior to the flaring parts of the ilia & the pelvic brim.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
The Bony Pelvis
Dimensions of the true pelvis are important for childbirth – must be large enough for the head to pass.
Outlet is the inferior opening of the pelvis.
Inlet is the superior opening.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Differing Characteristics Between the Male and Female Pelvis
Female inlet is larger & more circular.
Female pelvis as a whole is shallower & the bones are lighter & thinner.
Female ilia flare more laterally.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Differing Characteristics Between the Male and Female Pelvis
Female sacrum is shorter & less curved.
Female ischial spines are shorter & farther apart; thus the outlet is larger.
Female pubic arch is more rounded because the angle of the pubic arch is greater.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Bones of the Lower Limbs
Carry our total body weight when standing = thicker & stronger
The thigh has one bone – Femur (thigh bone)
Figure 5.24a–b
Bones of the Lower Limbs
Femur (thigh bone)
Proximal end has ball-like head, neck and greater & lesser trochanters. Trochanters are separated anteriorly by intertrochanteric line and posteriorly by intertrochanteric crest.
Figure 5.24a–b
Bones of the Lower Limbs
Trochanters, inter.-crest & gluteal tuberosity are sites for muscle attachment.
Slants medially as it runs downward to bring knees in line w/ body’s center of gravity. (more noticeable in females b/c of wider pelvis)
Figure 5.24a–b
Bones of the Lower Limbs
Distally are the lateral & medial condyles – articulate w/ tibia. (condyles separated by condylar fossa)
Anteriorly on distal end is the patellar surface – forms a joint w/ patella (kneecap)
Figure 5.24a–b
Bones of the Lower Limbs
The leg has two bones – tibia and fibula
Connected by interosseous membrane
Bones of the Lower Limbs
Tibia (shinbone)
At proximal end – medial & lateral condyles (separated by intercondylar eminence) articlulate w/ distal end of femur to form knee joint.
Figure 5.24c
Bones of the Lower Limbs
Patellar ligament attaches to tibial tuberosity (anter.)
Distally, a process called medial malleolus forms inner bulge of ankle.
Anterior surface has sharp ridge – anterior border (unprotected by muscle – so you can feel this)
Figure 5.24c
Bones of the Lower Limbs
Fibula
Figure 5.24c
Bones of the Lower Limbs
Foot – composed of tarsals, metatarsals & phalanges
Two important fxns.: supports body weight & serves as a lever allowing us to propel body forward when walking,etc.
Figure 5.25
Bones of the Lower Limbs
7 Tarsal bones
calcaneus (heelbone) &
Figure 5.25
Bones of the Lower Limbs
5 metatarsals form the sole
14 phalanges form the toes (each toe has 3, except the big toe)
Figure 5.25
Arches of the Foot
2 longitudinal (medial & lateral), 1 transverse
Ligaments bind foot bones together
Tendons of the foot muscles help to hold bones in arched position but allow for “springiness” – weak arches are referred to as “fallen arches” or “flat feet”
Figure 5.26