THE CRANIAL NERVES AND THEIR NUCLEI 193 



The Vestibular Nerve. The component fibers belong to the special somatic 

 afferent group and are proprioceptive. Cells of origin, in the vestibular ganglion, 

 are bipolar. Their peripheral branches run to the semicircular canals, utricle and 

 saccule. Their central branches terminate in the principal, lateral, superior, and 

 spinal vestibular nuclei. Some of them run without interruption to the cerebellum. 



The Cochlear Nerve. The component fibers belong to the special somatic 

 afferent group and are exteroceptive. Cells of origin, in the spiral ganglion of 

 the cochlea, are bipolar. Their peripheral branches end in the spiral organ of 

 Corti. Their central branches terminate in the ventral and dorsal cochlear nuclei. 



IX. The Glossopharyngeal Nerve. Superficial origin, from the rostral 

 end of the posterior lateral sulcus of the medulla oblongata in line with the 

 tenth and eleventh nerves. Composition (Fig. 120): 



1. General Visceral Afferent Fibers. Cells of origin in the ganglion petrosum, 

 peripheral branches form the general sensory fibers to the pharynx and posterior 

 third of the tongue, central branches run to the tractus solitarius and its nucleus. 



2. Special Visceral Afferent Fibers. Cells of origin in the ganglion petrosum, 

 peripheral branches to the taste buds of the posterior third of the tongue, central 

 branches, to the tractus solitarius and its nucleus. 



3. General Visceral Efferent Fibers. Cells of origin in the inferior salivatory 

 nucleus; fibers run to the otic ganglion, from the cells of which postganglionic 

 fibers carry the impulses to the parotid gland. 



4. Special Visceral Efferent Fibers. Cells of origin in the nucleus ambiguus. 

 Termination in the stylopharyngeus muscle. 



X. Vagus Nerve. Superficial origin from the rostral part of the posterior 

 lateral sulcus of the medulla oblongata in line with the ninth and eleventh and 

 just caudal to the ninth. Composition (Fig. 120) : 



1. General Somatic Afferent Fibers. Cells of origin in the ganglion jugulare; 

 peripheral branches to the skin of the external ear by way of the ramus auricularis; 

 central branches to the spinal tract of the trigeminal nerve and its nucleus. 

 According to Herrick, some of these fibers from the external ear run by way of 

 the glossopharyngeal nerve also. 



2. General Visceral Afferent Fibers. Cells of origin in the ganglion nodosum; 

 peripheral branches run as sensory fibers to the pharynx, larynx, trachea, esopha- 

 gus, and the thoracic and abdominal viscera ; central branches run to the tractus 

 solitarius and terminate in its nucleus. 1 



According to Wilson (1905) there are also special visceral afferent fibers in the vagus for 

 the taste buds of the epiglottis. These also terminate in the nucleus of the tractus solitarius. 



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