1894.] 



AlifATOMT OF ATHERUBA ArRIOAITA. 



687 



The brachial plexus (fig. 7, p. 688) is remarkable for its com- 

 plexity ; in other words, the different nerves of which it is composed 

 are not bound together into cords as in Man and the higher 

 mammals, but each one can be traced into the different nerve- 

 roots from which it is derived. 



The plexus is formed by the 5th, 6th, 7th, and 8th cervical, and 

 the greater part of the 1st dorsal nerve. 



Fig. 5. 



a. 



fP) 



The Brain. 

 a. From above. I b. From below. 



Fig. 6. 



The Brain from the side. 



The following are its branches : — 



The suprascapular nerve rises from the fifth and sixth cervical 

 and supplies the supra- and infraspinatus. 



The phrenic comes entirely from the 5th 0. and runs to the 

 diaphragm. The nerve to the subscapularis comes from the 5th C. 



