Pectoral Girdle and Upper Limb

Pectoral (Shoulder) Girdle

Composed of the clavicle and scapula; attaches the upper limbs to the axial skeleton at the sternum

Clavicle (Collarbone)

The only long bone that ossifies intramembranously (no marrow cavity); allows shoulder motion; acts as a shock-absorbing strut between the shoulder joint and trunk; the most commonly fractured bone in the body (often from FOOSH — fall on outstretched hand)

Scapula (Shoulder Blade)

Lies on the posterior aspect of the shoulder; supported by the clavicle; the acromion articulates with the clavicle; the glenoid cavity forms the shoulder joint

Humerus

Single bone of the upper arm; the proximal head articulates with the scapula's glenoid cavity (glenohumeral/shoulder joint); the distal end articulates with the radius and ulna at the elbow joint

Ulna

The medial bone of the forearm; the primary bone of the elbow joint; provides stability for forearm movements

Radius

The lateral bone of the forearm; can rotate during pronation and supination of the palm

Interosseous Membrane

Fibrous connective tissue attaching the radius to the ulna (and tibia to fibula), allowing some rotation

Carpals

The 8 wrist bones arranged in proximal and distal rows of four; allow wrist flexibility; the scaphoid is most frequently fractured (FOOSH injury)

Metacarpals

The 5 bones forming the palm of the hand

Phalanges

Bones of the fingers and toes; each finger except the thumb has proximal, middle, and distal phalanges; the thumb (pollex) has only proximal and distal phalanges

Carpal Tunnel

The passageway through which nine muscle tendons and the median nerve enter the hand from the forearm; inflammation causing compression leads to Carpal Tunnel Syndrome