804 



THE NERVOUS SYSTEM 



or accessory part of the nerve; those which arise from the ventral horn cells below 

 are described as the spinal part. The trunk of the spinal accessory fuses with the 

 vagus in the region of its two ganglia, and, before separation, contributes fibres (the 

 accessory part) to the trunk of the vagus. The accessory fibres are distributed as 

 motor fibres to the muscles of the larynx; the spinal part is distributed to the sterno- 



FIG. 599. SCHEME SHOWING THE RELATIVE SIZE AND POSITION OF THE NUCLEI OF ORIGIN (RED) 

 OF THE MOTOR AND THE NUCLEI OF TERMINATION (BLUE) OF THE SENSORY CRANIAL NERVES. 



XrCLEL'S OF OLFACTORY XERVE 



NUCLEUS OF OCULOMOTOR 

 NER VE 



NUCLEUS OF TROCHLEAR 



01- 



ROOT OF TRIHEMIXUS 



\ 1>1'LVI\'.\R 



\ THALAIiri 



LATEKM. <,/:.Y/r. 

 I'l.ATK 111 in Y 



\rn.Kfs Oh- si IT- 

 R1OH t'OLLICULCS 



SEXSOKY XCCLEI'.i Of 



.V OF VESTIBU- 

 LAll XKRl'E 



VEXTHAL 



a I- (in 'llLEAl! XER I 'E 



DORSAL NUCLEUS OF 

 COCHLEA R XERVE 



CHIEF MOTOR NUCLEUS OF- - 

 TRJGEMIXUS 



NUCLEUS OF FACIAL - 

 NUCLEUS OF ABDUCEXS 



NUCLEUS AMBIGUUS (VAGUS 

 AND GLOSSO-PHARYNGEUS) 



NUCLEUS OF HYPOGLOSSUS - 



- - NffLEffi A I..T. riXEREsE ( VAGUS 



AXli OLOSSO-PBASrjfCfSVS ) 



- SOLITARY TRA<'T ( l'Af,TS AXD 



GLO88O-PHARYNGEU8) 



NUCLEI'S OF Sl'lX.lL TRACT OF 

 TRIGEM1NUS 



NUCLEUS OF SPINAL ACCESSORY 



NERVE 



mastoid and trapezius muscles. The nucleus of the spinal accessory receives terminal 

 twigs of pyramidal fibres and is otherwise subjected to influences similar to those 

 affecting the cells giving origin to the motor roots of the spinal nerves. 



The vagus or pneumogastric and the glosso-pharyngeus, though they have 

 widely different peripheral distributions, are so similar in origin and central connec- 



