REGION OF PONS VAEOLII 



173 



and their mode of action will be considered when dealing with 

 the mechanism of circulation, respiration, and digestion. 



C. REGION OF PONS VAROLII 



This region consists of the upper part of the medulla 

 embraced by the transverse fibres of the middle peduncles of 

 the cerebellum (fig. 87). 



Dent 



Rest 



FIG. 87. Cross Section through Region of Pons, Cerebellum, and Fourth 

 Ventricle. S.V., superior vermis ; R.N., roof nucleus; Dent,, dentate 

 nucleus ; Rest., restiform body ; S.P., superior peduncle of cerebellum ; 

 Deit., Deiters' nucleus ; VI. , nucleus of the sixth nerve ; F., fillet ; 

 S.O., superior olive; D. T. and S.T., deep and superficial transverse 

 fibres ; P., pyramidal fibres. (After BRUCE.) 



Outgoing Fibres. 1. The fibres to the face muscles cross the 

 middle line to become associated with the various nuclei of 

 the cranial nerves. For this reason a tumour in one side of 

 the pons may cause paralysis of the face muscles on one side 

 and of the muscles of the rest of the body on the opposite side. 



