MYOLOGY j 101 



Shape. Long, fusiform, fleshy. * -^ \ // 



Action. Raises the wing. 



Pectoralis Tertius (Fig. 13, No. 6; Fig. 15, No. ^4, 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; inferiorly, 

 with the pectoralis secundus; internally, with the fascia of the sub- 

 clavius and the sternum. 



Shape. Fleshy, fusiform. 



A ction. Assists the pectoralis secundus in elevating the humerus. 



MUSCLES OF THE SCAPULAR REGION 



Coraco-humeralis Scapulo-humeralis 



Supraspinatus Subclavius 



Coraco-brachialis Teres minor 



Levator scapulae 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. 



