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 

 jimcture. 



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-hiuneral 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-brachiaUs 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. 



