MYOLOGY 103 



neath the neck of the scapula, it is attached by a small tendon to 

 the top of the ulnar tuberosity of the humerus in common with the 

 coraco-brachialis, with which tendon it fuses. 



Shape. Small, chunky. 



Relations. Anteriorly, with the tip of the scapula and behind the 

 coracoid head. Posteriorly, with the coraco-brachialis. 



Action. Aids in the downward stroke of the wing. 



Levator Scapulae. Location: Scapular region. 



Origin. By two strong digitations, one from each of the lateral 

 processes of the first cervical vertebra. 



Insertion. To the middle third of the inferior part of the blade 

 of the scapula. 



Shape. Small and flat. 



Relations. Inferior to the scapula. 



Action. Pulls the scapula forward, and with it the entire shoulder 

 girdle, which articulates like a hinge-joint at the costo-sternal 

 juncture. 



Thoraco-scapularis. Location. Lateral side of the chest. 



Origin. From the outer part of the lower half of the first free 

 rib, the outer side of the next succeeding rib and its epineural append- 

 age, and from a similar surface on the next rib. 



Insertion. By a broad, flat tendon which passes between the 

 two divisions of the subscapularis and inserts at a point at the 

 juncture of the anterior and middle third of the outer margin of 

 the scapula. 



Shape. Broad, flat. 



Relations. Internally, with the ribs and the scapula. 



Action. When the scapula is fixed it is a muscle of inspiration. 

 When the ribs are fixed, it draws the scapula downward. . 



Subscapularis. Location. Scapulo-humeral region. 



Origin. From the anterior and outer half of the scapula. 



Insertion. By a strong and subcylindrical tendon to the top of 

 the ulnar tuberosity of the humerus close to the combined tendons 

 of the coraco-brachialis and teres minor. 



Shape. A large and powerful muscle. 



Relations. The flat tendon of the thoraco-scapularis divides the 

 posterior portion of the belly into two portions. 



Action. A powerful rotary muscle of the head of the humerus; 

 aids in keeping the humeral head in the glenoid cavity. 



