Nerves, Spinal Coed, Brain and Other Ganglia 



93 



The latter division (purely efferent) arises from the spinal nerve roots 

 down to the sixth cervical segment. The bulbar accessory, which ulti- 

 mately becomes a part of the vagus, arises, together with the efferent 

 fibers of the vagus and the glossopharyngeal, from the cells of the dorsal 

 nucleus of the tenth and eleventh nerves (lying in the floor of the fourth 

 ventricle external to the nucleus of the twelfth nerve), and the nucleus 

 ambiguus, which lies deeper in the medulla. 



The afferent fibers of the vagus arise from the ganglion trunci vagi 



TO VERMIS 



TO HEMISPHERE 



FIBRES OF 



VESTIBULAR 



ROOT 



NERVE 

 ENDINGS 

 IN MACUL/E 

 & AMPULLA 



p.tt> 



Fig. 75. Diagram of the course and connections of the fibers of the vestibular 

 branch of the eighth (auditory) nerve. (Quain's Anatomy.') 



r, restiform body. V, descending root of fifth nerve, p, principal nucleus of vesti- 

 bular branch, d, fibers of descending vestibular branch, n, d, a, cell of descending 

 vestibular nucleus. D, nucleus of Deiters. B, nucleus of Bechtereff. n, /, nucleus 

 tecti (fastigii) of the cerebellum, p, I, b, posterior (dorsal) longitudinal bundle. 



and the jugular ganglion, which lie on the nerve trunk. The afferent 

 fibers of the glossopharyngeal arise from the ganglion petrosum and the 

 ganglion superius. The afferent nucleus in the brain stem for both 

 nerves is a column of gray matter lateral to the hypoglossal nucleus in the 

 floor of the fourth ventricle just below the " ala cinerea." From this 

 nucleus descending fibers (the fasciculus solitarius or " respiratory 

 bundle of Gierke"), may be traced downwards as far as the cervical 

 part of the spinal cord. 



The efferent fibers of the glossopharyngeal are distributed to the 



