NERVES OF THE SHOULDER. 



737 



These nerves vary considerably as to their number and 

 origin, in the axillary plexus ; FlG - 238. 



hence the diversity of the state- 

 ments of different anatomists 

 in their descriptions of them. 



The thoracic nerves come 

 from the plexus, about its 

 middle, and vary in number 

 from two to five. They are 

 divided into anterior and pos- 

 +terior branches; the former 

 supply the subclavian and pec- 

 toral muscles, and the latter 

 go to the serratus magnus, 

 posterior scalenus, and rhom- 

 boid muscles. 



The supra-scapular comes 

 from the upper portion of the 

 plexus, and accompanies the 

 superior scapular artery to 

 the notch or foramen in the 

 -superior costa of the scapula, 

 through which it passes to 

 supply the supra-spinatus. It 

 also passes behind the neck of 

 the scapula to be distributed 

 upon the infra-spinatus and 

 teres minor muscles. 



The sulscapular nerves are 

 three or four in number ; they 

 vary in their origin, but mostly arise either from the 

 upper or central portions of the plexus. They are distrib- 



FIG. 238 represents the nerves of the Superior Extremity. A Axillary ar- 

 tery. B Brachial artery, b Supra-scapular nerve, c Subscapular. d Inter 

 nal cutaneous, e Musculo or external cutaneous nerve. / Circumflex, g 

 Ulnar nerve, h Superficial branch of the latter on the hand. I Median nerve, 

 m Anterior interosseous nerve, o Musculo-spiral nerve, p Radial, q Posterior 

 interosseous nerve. 



47 



