

CEKYICAL PLEXUS. 



697 



vical nerves. Two independent branches enter the lateral surface of the muscle 

 in the posterior triangle. , (4) To the scaleni (medius and posterior), from the third 

 and fourth cervical nerves. 



The communicating branches are three in number. They join the accessory 

 nerve in three situations: (a) A branch from the second cervical nerve to the 

 sterno-mastoid joins the accessory nerve under cover of that muscle. (&) Branches to 

 the trapezius from the third and fourth nerves are connected with the accessory 

 nerve in the posterior triangle, (c) Branches from the same nerves join the nerve 

 under cover of the trapezius muscle. 



r vical branch of facia ,-- 

 ferves to levator scapulae- 



Anterior supra- 

 clavicular nerve 



- Greater occipital 



Lesser occipital 

 Third occipital 

 Great auricular 



N. cutaneus colli 

 Nerves to levator scapulae 



Accessory nerve 

 Communicating branch to accessory 



> Nerve to trapezius 



. Posterior supra-clavicular 

 nerve 



Middle supra-clavicular nerve 

 Supra-scapular 



FIG. 612. THE NERVES OF THE SIDE OF THE NECK. 



The medial branches of the plexus also comprise muscular and communi- 

 branches. The first cervical nerve assists in the formation of this series of 



jrse 



, forming a slender loop with part of the second nerve in front of the trans- 

 process of the atlas. 



Communicating Branches. (a) With the sympathetic. Gray rami communi- 

 ntes pass to each of the first four cervical nerves, near their origins, from the 

 .perior cervical ganglion or from the trunk below the ganglion. (&) With the 

 vagus nerve. The ganglion nodosum of the vagus nerve may be connected by a 

 slender nerve with the loop between the first two cervical nerves. This communica- 

 tion is not constant, (c) With the hypoglossal. An important communication 

 occurs between the hypoglossal nerve and the loop between the first and second 



