CH. XLIV.] 



THE AUDITORY NERVE 



643 



path is continued by new axons that arise from these cells. Those 

 from the accessory nucleus enter the trapezium, and pass in it partly 

 to the superior olive and trapezoid nucleus of the same side, but 

 mainly to the corresponding nuclei of the opposite side ; some fibres 

 end here, others traverse the nuclei, and merely give off collaterals to 

 them ; they then turn upwards in the lateral fillet, and so reach the 

 inferior C. quadrigemina. The fibres which arise in the acoustic 

 tubercle pass superficially over the floor of the ventricle, forming the 

 striae acousticce; having crossed the raphe, they join the fibres from the 

 accessory nucleus in their course to the superior olive and fillet. 

 Here again, however, a few fibres pass to the fillet of the same side. 



tub. 



FIBRES TO NUCL.LEMNISCI 



&CORPORA QUADRIGEMINA 



NERVE-ENDINGS 



IN ORGAN OF CORTt 



FIG. 467. Cochlear root of the auditory nerve, r, restiform body ; V, descending root of the fifth 

 nerve; tub. ac., acoustic tubercle; n. ace., accessory nucleus ; s.o., superior olive; n.tr., trapezoid 

 nucleus; n.VI., nucleus of the sixth nerve; VI., issuing fibre of sixth nerve. (Schiifer.) 



The vestibular nerve arises from the bipolar cells of the ganglion 

 of Scarpa in the internal ear. The peripheral axons ramify among 

 the hair cells of the epithelium in the utricle, saccule, and semi- 

 circular canals. The central axons enter a collection of small nerve- 

 cells between the restiform body and the descending root of the fifth ; 

 this is termed the principal nucleus; here they bifurcate; the 

 descending branches run towards the lower part of the bulb, and 

 arborise around the cells of the neighbouring grey matter (descending 

 vestibular nucleus). The ascending branches pass upwards in the 

 restiform body to the cerebellum, in their course giving off many 

 collaterals which form synapses with the large cells of two nuclei 

 near the outer angle of the ventricular floor, and known as the 

 nucleus of Deiters and nucleus of Bechterew respectively. The fibres 



