_The Pectoral Girdle_ and _Anterior Limb_. The pectoral girdle (Fig. 27) is of a very simple type, consisting, unless the episternum (interclavicle) be counted, of but two bones, the _scapula_ (_s_) and _coracoid_ (_c_). The former consists of an upper, flat, paddle-shaped portion and a thicker lower portion which articulates anteriorly with the coracoid, and posteriorly forms about half of the notch-like glenoid cavity. The dorsal edge of the flattened portion is continued as a small, cartilaginous suprascapula. The coracoid is a flattened bone, wide at either end and narrow in the middle, so that in a dorsal view it is shaped like an hourglass. It is decidedly curved, with the convex side down. Its outer edge articulates with the scapula and is thickened to form the anterior border of the glenoid cavity. Its median end is attached to the sternum. Near its scapular articulation there is a well-marked foramen that passes entirely through the bone. The _episternum_ (_e_) or interclavicle was described in connection with the sternum and ribs. There is no clavicle nor other coracoid elements. [Illustration: FIG. 27. PECTORAL GIRDLE AND ANTERIOR LIMB. _c_, coracoid; _ce_, centrale; _cl_, claw; _e_, episternum; _h_, humerus; _m_, metacarpals; _p_, pisiform; _r_, radius; _r′_, radiale; _s_, scapula; _u_, ulna; _u′_, ulnare.] The _anterior limb_ consists of the usual parts,--the upper arm, forearm, and manus. The _humerus_ (Fig. 27, _h_) is rather thick in proportion to its length; it has an elongated articular surface at its proximal end for articulation with the glenoid cavity, and a larger, somewhat bilobed surface for articulation with the radius and ulna. On its ventral side, near the proximal end, is a very prominent protuberance, the deltoid ridge. The _ulna_ (_u_) is slightly heavier and longer than the radius and forms the greater part of the elbow joint and about half of the wrist joint. Its proximal end is considerably larger than the distal, but has no olecranon process. Its distal end articulates with the ulnare and pisiform. The ulna as a whole is slightly curved, while the radius is quite straight. The _radius_ (_r_) consists of a cylindrical shaft with enlargements of about equal size at the ends. The proximal end articulates with the side of the ulna and with the humerus; the distal end with the radiale.