150 HUMAN ANATOMY. 



SUBCLAVIUS.- Origin, from cartilage of the first rib ; inser- 

 tion, under surface of the clavicle, about its middle third ; action, 

 depresses the shoulder, and draws clavicle forward and down- 

 ward; nerve, branch from the union of the fifth and sixth 

 cervical. 



SERRATUS MAGNUS. Origin, by nine muscular portions, 

 from the outer surface of the eight upper ribs (two divisions 

 being from the second rib) and from the upper intercostal apo- 

 neurosis ; insertion, by three divisions upper portion into supe- 

 rior angle of the scapula, middle portion into posterior portion 

 of the scapula between the inferior and superior angles, lower 

 portion into the inferior angle of the scapula; action, raises the 

 vertebral border and carries the scapula forward; nerve, the pos- 

 terior thoracic. 



DELTOID. Origin, from the outer third of the clavicle and 

 from the outer part of the acromion process and the lower bor- 

 der of the scapular spine; insertion, into the outer side of the 

 shaft of the humerus, about its middle into the -deltoid tubercle; 

 action, raises the arm; nerve, the circumflex. 



SUBSCAPULARIS. Origin, from the internal two-thirds of 

 the subscapular fossa; insertion, into the lesser tuberosity of the 

 humerus; action, rotates the head of the humerus inward; 

 nerves, upper and lower subscapular. 



SUPRASPINATUS. Origin, from inner two-thirds of supra- 

 spinous fossa; insertion, into the uppermost facet of the great 

 tuberosity of the humerus; action, assists in raising the arm 

 and fixing the head of the humerus; nerve, the suprascapular. 



INFRASPINATUS. Origin, from the inner two-thirds of the 

 infraspinous fossa; insertion, into the middle facet of the great 

 tuberosity ; action, rotates the head of the humerus outward ; 

 nerve, supra-scapular. 



TERES MINOR. Origin, posterior surface of the upper two- 

 thirds of the axillary border of the scapula; insertion, into the 

 lowest facet of the great tuberosity; action, rotates the head of 

 the humerus outward; nerve, the circumflex. 



TERES MAJOR. Origin, posterior surface of the inferior 

 angle of the scapula; insertion, into the posterior bicipital ridge 

 of the humerus; action, draws the humerus backward and down- 

 ward, assisting the latissimus dorsi ; nerve, the lower subscapular. 



HUMERAL REGION. 



CORACO-BRACHIALIS. Origin, from apex of the coracoid 

 process of the scapula; insertion, into the inner side of the 

 middle of the shaft of the humerus, between the origin of the 



