836 



THE NERVOUS SYSTEM. 



External anterior thoracic. 



Internal anterior thoracic. 



- cutaneous. 



Musculo-spiral. 

 Posterior 



interosseous. 



Anterior 

 interosseous. 



FIG. 500. Nerves of the left upper extremity. 



spiral nerve is subsequently joined by the posterior division of the inner trunk, 

 formed by the union of the eighth cervical and first dorsal. 



