CHAPTER VII. 



TRIFACIAL, OR TRIGEMINAL NERVE. 



Physiological anatomy of the trifacial Properties and functions of the trifacial 

 Division of the trifacial within the cranial cavity Immediate effects of 

 division of the trifacial Remote effects of division of the trifacial Effects 

 of division of the trifacial upon the organs of special sense Division of the 

 trifacial before and behind the ganglion of Gasser Communication with 

 the sympathetic at the ganglion of Gasser Explanation of the phenomena 

 of disordered nutrition after division of the trifacial Cases of paralysis of 

 the trifacial in the human subject. 



A SINGLE nerve, the large root of the fifth pair, called 

 the trifacial, or the trigeminal, gives general sensibility to 

 the face and the head as far back as the vertex. This is one 

 of the most interesting of the cranial nerves, and is one of 

 the first that was experimented upon by physiologists. It 

 is interesting, not only as the great sensitive nerve of the 

 face, but from its connections with other nerves and its re- 

 lations to the organs of special sense. In studying the 

 physiology of this nerve, we must necessarily begin with its 

 physiological anatomy. 



Physiological Anatomy. The apparent origin of the 

 large root of the fifth is from the lateral portion of the pons 

 Yarolii, posterior and inferior to the origin of the small root, 

 from which it is separated by a few transverse fibres of white 

 substance. The deep origin is far removed from its point of 

 emergence from the encephalon. The roots pass entirely 

 through the substance of the pons, from without inward and 

 from before backward, without any connection with the 

 fibres of the pons itself. By this course it reaches the me- 



