CHAPTER XX 

 TRIFACIAL NERVE PNEUMOGASTRIC NERVE 



Trifacial (large root of the fifth nerve) Physiological anatomy Properties and uses of the 

 trifacial Immediate effects of division of the trifacial Remote effects of division of the 

 trifacial Pneumogastric (tenth nerve) Physiological anatomy Properties and uses 

 of the auricular nerves Properties and uses of the pharyngeal nerves Properties and 

 uses of the superior laryngeal nerves Properties and uses of the inferior, or recurrent 

 laryngeal nerves Properties and uses of the cardiac nerves Depressor nerve Proper- 

 ties and uses of the pulmonary nerves Effects of division of the pneumogastrics on respira- 

 tion Effects of faradization of the pneumogastrics on respiration Properties and uses 

 of the oesophageal nerves Properties and uses of the abdominal nerves Influence of the 

 pneumogastrics on the liver Influence of the pneumogastrics on the stomach and intes- 

 tines Effects of faradization Influence of section of the pneumogastrics on the move- 

 ments of the stomach Influence of the pneumogastrics on the small intestine. 



TRIFACIAL (LARGE ROOT OF THE FIFTH NERVE) 



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

 the trigeminal, gives general sensibility to the face and to the head as 

 far back as the vertex. This nerve is important, not only as the great 

 sensitive nerve of the face, but on account of its connections with other 

 nerves and its relations to the organs of special sense. 



Physiological Anatomy. The apparent origin of the large root of 

 the fifth is from the lateral portion of the pons Varolii, at a point pos- 

 terior and inferior to the origin of the small root, from which it is sepa- 

 rated 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 the fibres reach the bulb, where 

 the roots divide into three bundles. The anterior bundle passes from 

 behind forward, between the anterior fibres of the pons and the cere- 

 bellar portion of the restiform bodies, to anastomose with the fibres of 

 the auditory nerve. The other bundles, which are posterior, pass, one 

 in the anterior wall of the fourth ventricle to the lateral tract of the 

 bulb and the other, becoming grayish in color, to the restiform bodies, 

 from which they may be followed as far as the point of the calamus 

 scriptorius. A few fibres from the two sides decussate at the median 



521. 



