_Insertion._—The fibers converge into a tendon, which passes upward around the coracoid to its posterior through a canal formed by the scapula, the coracoid, and the clavicle, the foramen triosseum (Fig. 15, No. _A_, 7). This tendon then passes outward and downward, and becoming flat, inserts to the humerus just anterior to the radial crest and nearer to the humeral head than does the pectoralis major. _Relations._—Internally, with the breast-bone; externally, with the pectoralis major; and superiorly, with the pectoralis tertius. _Shape._—Long, fusiform, fleshy. _Action._—Raises the wing. =Pectoralis Tertius= (Fig. 13, No. 6; Fig. 15, No. _A_, 5). _Location._—On the antero-lateral side of the sternum. _Origin._—From the anterior half of the exterior of the body of the sternum, from the fascia of the subclavius on the outer border of the costal process, and from the outer, lower third of the coracoid process. _Insertion._—The fibers pass upward to the outer side of the coracoid, and becoming tendinous as they reach the humerus, by a strong flattened tendon insert to the ulnar crest of the humerus on the proximal margin at about a middle point of the pneumatic fossa. _Relations._—Externally, with the pectoralis major; interiorly, with the pectoralis secundus; internally, with the fascia of the subclavius and the sternum. _Shape._—Fleshy, fusiform. _Action._—Assists the pectoralis secundus in elevating the humerus. MUSCLES OF THE SCAPULAR REGION Coraco-humeralis Scapulo-humeralis Supraspinatus Subclavius Coraco-brachialis Teres minor Levator scapulæ Thoraco-scapularis Subscapularis =Coraco-humeralis.= _Location._—The scapulo-humeral region. _Origin._—From the outer side of the head of the coracoid, supero-laterally to the long head of the biceps. _Insertion._—To the palmar part of the head of the humerus just inside of the insertion of the pectoralis major. _Shape._—A delicate subcylindrical muscle. _Relations._—Superior to the head of the humerus. _Action._—Aids in extending the humerus. =Scapulo-humeralis= (Fig. 14, No. 10). _Location._—The scapulo-humeral region. _Origin._—From the inner side of the neck of the scapula just within the head of the deltoid. _Insertion._—Passing over the top of the shoulder-joint it is inserted to the palmar part of the humeral head between the insertion of the pectoralis major and the pectoralis secundus. _Shape._—Narrow, flat ribbon. _Relations._—Along the upper margin of the larger portion of the deltoid. _Action._—Aids in extending the humerus. =Supraspinatus= (Fig. 19, No. 22). _Location._—Scapular region. _Origin._—From the superior surface and outer third of the scapula.