Zoology · Ch 9 — Locomotion and Movement
The Pectoral girdle and Upper limb
The Pectoral girdle and Upper limb
The Pectoral girdle and Upper limb
The pectoral girdle is formed of two halves, each consisting of a clavicle (collar bone) and a scapula (Figure 9.10). Both bones are light, giving the upper limb a degree of mobility unmatched elsewhere in the body. The scapula is a large, thin, triangular bone lying on the dorsal surface of the ribcage between the second and seventh ribs; it bears a raised ridge, the spine, which projects outward as the flattened acromion process (where the clavicle articulates) and, just below it, a depression called the glenoid cavity, which receives the head of the humerus to form the shoulder joint. The clavicle itself is a long, doubly curved bone lying horizontally, linking the axial skeleton to the appendicular skeleton. …
What this figure shows. Own-words cover: one side of the pectoral girdle and the attached arm, labelling the scapula with its acromion process and glenoid cavity, the clavicle articulating with the acromion, the shoulder joint (glenoid cavity plus head of humerus), the humerus, the elbow joint, the olecranon process at the top of the ulna, the radius, the wrist joint, and the hand bones — carpal …