VEINS, LYMPHATICS, ARTERIES, AND NERVES 



77 



referred to as CIV, C.V, C.VIII, and T.I). As in man, the 

 relations of the nerves comprising the plexus are often very 

 variable and additional fibers from the more craniad cervical and 

 more caudad thoracic spinal nerves usually enter it. Fibers of 

 C.V and CIV join the brachial plexus, but most of the branches 

 of these vertebral nerves pass to the cleidomastoid and other 

 muscles and integument of the neck. All nerves from the 

 superior limb communicate with the central nervous system 

 through this plexus, and most of the nerve trunks supplying the 



Fig. 24. — Principal nerves of left brachial plexus. I, first rib; IV-VIII, 

 cervical spinal nerves; AA, axillary artery; AT, anterior thoracic; AX, axillary; 

 LAT, long anterior thoracic; M, median; MBC, Wrisberg's n. (6); MC, musculo- 

 cutaneous; MS, musculospiral ; R, radial; SR, superficial radial; SP, suprascap- 

 ular; T, branches to triceps (n.8); TI, first thoracic spinal nerve; TD, 

 thoracodorsal; U, ulnar; VA, vertebral a. 



brachium and antibrachium converge with the cord formed by 

 T.I and C.VIII. This cord is easily recognized since it is the 

 most caudad of the three great nerve cords in the axillary region 

 and arises on two sides of the first rib. At least twenty impor- 

 tant nerves supply the muscles of the superior limb, but all of 

 those described here supply, in general, the same regions in the 

 rabbit as in man. Commonly, the larger nerves follow the gen- 

 eral course of the arteries and are often given the same name as 

 that of the corresponding artery. The origin, course, and 

 distribution furnish the necessary information for identifying 



