Skeleton

The bones of the upper and lower limbs along with their girdles constitute the appendicular skeleton. The appendicular skeleton is composed of bones. (a) The Pectoral girdle The upper limbs are attached to the pectoral girdles. These are very light and allow the upper limbs a degree of mobility not seen anywhere else in the body.

The girdle is formed of two halves . Each half of the pectoral girdle (Figure . ) consists of a clavicle or collar bone and a scapula . The scapula is a large, thin, triangular bone situated in the dorsal surface of the ribcage between the second and seventh ribs.

It has a slightly elevated ridge called the spine which projects as a flat, expanded process called the acromion . The clavicle articulates with this process. Below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus to form the shoulder joint. Each clavicle is a long slender bone with two curvatures which lies horizontally and connects axial skeleton with appendicular skeleton.