630 



STRUCTURE OF THE BULB, PONS, AND MID-BRAIN fCH. XLFV. 



return once more to the cranial nerves, in order that we consider their 

 origin and function in greater detail. 



But this diagram will give a general idea of the positions of the 



3rd. Ventricle 



III 



IV 



Vm. 



VI 



Va. 



VII 



N.D. 



Vlllm. 



C.G. 



S/r. A 



Lateral column 

 Funiculus cuneatus 

 Funiculus gracilis 



FIG. 459. Diagram to show the position of the nuclei of the cranial nerves (after Sherringtou). The 

 medulla and pons are viewed from the dorsal aspect, the cerebrum and cerebellum having been cut 

 away. The nuclei (sensory coloured red, and motor blue) are represented as being seen through 

 transparent material. C.Q. a., anterior corpus quadrigeminum ; C.Q. p., posterior corpus quadri- 

 geminum ; C.G., corpus geniculatum ; v.v., value of Vieussens ; Z.c., locus coeruleus ; e.t., eminentia 

 teres ; str. A., striae acousticse. S.P., M.P., and I. P., superior middle and inferior cerebellum 

 peduncles respectively cut through. The numerals III. to XII. indicate the nuclei of the respec- 

 tive cranial nerves, all shown on the leftside except the accessory-vago-glossopharyngeal IX., X., XL, 

 which to avoid confusion is placed on the right side. Vm. is the motor nucleus of the fifth nerve ; 

 Vd., the sensory nucleus of the same nerve with its long descending root; Vlllm., the median 

 nucleus of the auditory nerve; N.D. Nucleus of Deiters; n. amb. nucleus ambiguus. The position 

 of the descending root of the ninth and tenth (fasciculus solitarius) is also indicated (/. s ). 



nuclei. It will be noticed that the so-called sensory nuclei (coloured 

 red) are in the minority ; they comprise the sensory nucleus of the 

 fifth nerve with its long descending (formerly called ascending) root, 



