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Chapter 8
The Appendicular Skeleton
Table 8.1
The Appendicular Skeleton
o Limbs (appendages)
o Pectoral girdle
o Pelvic girdle
The Pectoral (Shoulder) Girdle
o Composed of two bones
 Clavicle – collarbone
 Scapula – shoulder blade
o These bones allow the upper limb to have exceptionally free movement
Pectoral Girdle
o Supports the arm & links it to the axial skeleton
o contains the clavicle and the scapula
 Sternoclavicular joint – medial end of clavicle with sternum
 Acromioclavicular joint – lateral end of clavicle with scapula
 Glenohumeral joint – scapula with humerus
Bones of the Shoulder/Pectoral Girdle
o Clavicle
 Collarbone
 S-shaped bone
 Easily palpated on upper thorax
 Braces shoulder
 Most commonly fractured bone
o Scapula
 Triangular plate
 Overlies ribs 2-7
 Superior, medial, lateral borders
 Superior, inferior, lateral angles
 Acromion
 Coracoid process
 Glenoid cavity
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Bones of the Shoulder Girdle
o Upper Limbs
 Four regions containing 30 bones/limb
 Brachium: shoulder to elbow (humerus)
 Antebrachium: forearm (radius, ulna)
 Carpus: wrist (8 carpal bones)
 Manus: hand (19 bones-5 metacarpals, 14 phalanges)
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Bones of the Upper Limb
o The arm is formed by a single bone
 Humerus
 Humerus
o The forearm has two bones
 Ulna
 Radius
 Radius and Ulna
 Bones of the Upper Limb
o The hand
 Carpals – wrist
 Metacarpals – palm
 Phalanges – fingers
 Carpal Bones
 Scaphoid
 Lunate
 Triquetrum
 Pisiform
 Trapezium
 Trapezoid
 Capitate
 Hamate
 hamulus
o Metacarpals and Phalanges
 Metacarpals
 Bones of palm
 I: base of thumb
 V: base of little finger
 Base: proximal end
 Body: shaft
 Head: distal end
 Form knuckles
o Phalanges
 Bones of fingers
 Pollex
o Thumb
 Two bones
 Three bones in all others
o II to V
 Proximal
 Middle
 Distal
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Bones of the Pelvic Girdle
o Hip bones
 Composed of three pair of fused bones
 Ilium
 Ischium
 Pubic bone
o The total weight of the upper body rests on the pelvis
 Protects several organs
 Reproductive organs
 Urinary bladder
 Part of the large intestine
Pelvic Girdle
o 3 Bones:
o Two Hip (coxal) bones
 Os coxae
o Sacrum
Pubic symphysis
Protects viscera of pelvic cavity
Hip Bone
 Ilium
 Ischium
 Pubis
o Acetabulum
 Obturator foramen
Pelvis and Sexual Dimorphism
o Female
 Adapted to childbirth
 Wider
 Shallower
 Larger pelvic inlet and outlet
Lower Limb
o Four regions with 30 bones/limb
 Femoral: thigh
 Crural: knee to ankle
 Tarsal (tarsus): ankle
 Pedal (pes): foot
Femur and Patella
o Femur – longest and strongest bone
 Head forms ball-and-socket joint (acetabulum)
o Patella – kneecap
Tibia and Fibula
Ankle and Foot
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Pathology
o Amelia – complete absences of 1 or more limbs
o Meromelia – partial absence of limb
o Polydactyly – extra fingers or toes
o Syndactyly – webbed digits
o Clubfoot (talipes) – feet are adducted and plantar flexed with soles turned
medially
Review Questions
o The pectoral girdle consists of two bones? What are they called?
 Humerus & sternum
 Scapula and clavicle
 Brachium and antebrachium
 Ilium and ischium