THE CRANIAL NERVES AND THEIR NUCLEI 



189 



of Bechterew, (4) the lateral nucleus of Deiters, and (5) the cerebellum (Figs. 

 130, 136). 



The principal, medial, or dorsal vestibular nucleus is very large. It lies sub- 

 jacent to the major portion of the area acustica and belongs, therefore, to both 

 the pons and the medulla oblongata (Figs. 89, 103, 107). The gray matter, 

 associated with the descending branches from the vestibular nerve and lying on 

 the medial side of the restiform body, constitutes the spinal or descending 

 vestibular nucleus. Along with the descending fibers it can be followed in serial 



Nuc. of oculomotor _ 

 neroe 



Nuc. of trocMear nerve -^- 



Brachium 



Nuc. of abducens nerve. 



Rhomboid fossa' 



Medulla oblongata- 



Superior colliculus 



Inferior colliculus 



Med. longitudinal 

 - " ' fasciculus 



Superior vestibular 



Vestibulocerebellar 

 tract 



4 Lateral vestibular nuc. 



" Vestibular nerve 



' Spinal vestibular nuc. 



Principal vestibular 

 nucleus 



Fig. 136. Diagram of the nuclei and central connections of the vestibular nerve. (Based on 



figures by Herrick and Weed.) 



sections as far as the rostral extremity of the nucleus gracilis. The lateral vestib- 

 ular nucleus of Deiters is situated close to the restiform body at the point where 

 the fibers of the vestibular nerve begin to diverge (Fig. 107). It is composed of 

 large multipolar cells like those found in motor nuclei. Directly continuous with 

 the medial and lateral nuclei is a mass of medium-sized cells, the superior vestib- 

 ular nucleus of Bechterew, located in the floor and lateral wall of the fourth 

 ventricle lateral to the abducens nucleus, and the emergent fibers of the facial 

 nerve (Fig. 108). It extends as far rostrad as the caudal border of the main 

 sensory nucleus of the trigeminal nerve (Weed, 1914). 



