Appendicular Skeleton

Appendicular Skeleton• The appendicular skeleton consists of

the bones of the limbs and bones that anchor the limbs to the axial skeleton.

• Pectoral girdle: scapula, clavicle.

• Upper limbs: humerus, radium, ulna, carpals, metacarpals, phalanges.

• Pelvic girdle: coxal bones.

• Lower limbs: femur, tibia, fibula, patella, tarsals, metatarsals, phalanges.

Figure 7.42

Pectoral Girdle

• Clavicles: collar bones that attach the sternum to the shoulder anteriorly.

• Scapulae: shoulder blades with two processes.– Acromion process: tip of the shoulder.– Coracoid process: attaches to the clavicle

and provides attachments for muscles.– Glenoid fossa articulates with the humerus.

Upper limb

• Humerus: upper arm bone, articulates with the glenoid fossa of the scapula

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Upper limb cont.

• Radius: thumb side of the forearm, articulates with the capitulum of the humerus and the radial notch of the ulna

• Ulna: longer bone of the forearm, olecranon and coronoid processes articulate with the humerus

Hand

• Carpal bones: eight small bones of the wrist.

• Metacarpal bones: five bones, the framework of the palm.

• Phalanges: finger bones, three in each finger (proximal, middle, distal phalanx), two in the thumb.

Figure 7.47

Pelvic Girdle

• Coxal bones: two hips bones composed of three fused bones.

– Ilium: superior part of the coxal bone.

– Ischium: lowest portion of the coxal bone.

– Pubis: anterior part of the coxal bone. The two pubic bones joint at the symphysis pubis.

Figure 7.49Obturator foramen

(bone) Pubis

Iliac crest

Figure 7.49

Lesser sciatic notch

Inferior iliac notch

Pubic tubercle

Superior iliac notch

Male and Female Pelvis• Female iliac bones are more flared. “Hips

are wide”• female pubic arch angle is greater.• The sacral curvature is shorter and flatter.

• greater distance between the ischial spines and tuberosities in the female.

• The differences create a wider pelvic cavity in all diameters

• Larger pelvic brim

WHY???

Figure 7.51

Lower Limb

• Femur: thigh bone, longest bone

• Patella: kneecap, located in a tendon, femur, tibia, and patella form the knee joint

• Tibia: shinbone, lateral malleolus forms the ankle

• Fibula: slender bone lateral to the tibia, not part of the knee joint

Figure 7.52

Popliteal surface

Linea aspera (posterior)

• Osgood schlatter disease– Swelling of bony projection of tibia below knee– Due to over use of thigh muslces– More common in teens b/c of rapid bone

growth

Foot

• Tarsal bones: seven small bones in the ankle. The calcaneus (heel bone) is the largest, located below the talus.

• Metatarsal bones: elongated bones that form the arch of the foot.

• Phalanges: each toe has three except the great tow which has two.

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Figure 7.55

• Tarsus and metatarsus: arranged and bound by ligaments to form arch

• Plantar fascitis: flat foot “fallen foot”– Weakened tissue, constant or heavy weight

applied to foot

Life-Span Changes

• Calcium levels fall through life and the skeleton loses strength.

• Osteoclasts outnumber osteoblasts.

Life-Span Changes

• By age 35, everyone loses bone mass. Women lose bone mass faster between menopause and age seventy.

• Trabecular bone is lost before compact bone.