688 TR1GEMINAL NERVE. 



always preceded by a sense of tickling in the nose. The same result may 

 be brought about, in addition to direct irritation, also by dilatation of the 

 vessels of the nose. The latter occurs readily from the action of cold 

 upon the external integument. The vascular dilatation is later on as- 

 sociated with increased secretion from the nasal mucous membrane. 

 Irritation of the nasal nerve excites also flow of tears reflexly. Irrita- 

 tion of the nasal branches causes finally also expiratory cessation of the 

 respiratory movements. 2. The vasodilators of the nose pass with the 

 sensory fibers of the ganglion; they are derived principally from the 

 sympathetic root. 3. The motor branches descend, through the pos- 

 terior palatine nerve in the pterygopalatine canal and give off motor 

 fibers (h) to the elevator of the veil of the palate and the azygos uvulae. 

 The muscle-sense fibers are supplied by the trigeminus. Spasmodic con- 

 ditions in these muscles are said to cause paroxysmally crackling sounds 

 in the ear. 4. Filaments representing gustatory fibers pass also from the 

 intermediate portion of the facial nerve to the gums. 5. The vaso- 

 motors of this entire area are derived from the sympathetic root, there- 

 fore from the cervical sympathetic. 6. The trigeminus-root furnishes 

 the secretory nerves for the mucous glands of the nasal mucous mem- 

 brane. Irritation excites secretion, while resection of the trigeminus 

 diminishes secretion and causes at the same time atrophic degeneration 

 of the mucous membrane. Accordingly trophic functions for the mucosa 

 have also been attributed to the trigeminus. 



Feeble electric irritation of the exposed ganglion causes abundant secretion 

 of mucus and elevation of temperature in the nose, together with dilatation of 

 the vessels. After division of the trigeminus, redness of the nasal mucous mem- 

 brane on the same side occurs. This is probably due to the fact that penetrating 

 dust or secreted nasal mucus is not removed from the nose through reflex influences, 

 but remains and causes irritation and inflammation. 



The third, or inferior maxillary, division (g) unites all of the motor 

 filaments of the fifth nerve, with a number that are sensory, into a 

 plexus, from which are given off: 



1 . The recurrent nerve, which arises from the sensory root and enters 

 the skull through the spinous foramen and further on with the recurrent 

 nerve of the second division supplies the dura with sensory filaments. 

 From it pass also filaments through the petrososquamous fissure to the 

 mucous membrane of the mastoid cells. 



2. Motor branches for the muscles of mastication; the masseteric 

 nerve, the two deep temporal nerves, the external and internal ptery- 

 goid nerves. The muscle-sense fibers are probably derived from the 

 sensory fibers. 



3. The buccinator is a sensory nerve for the mucous membrane of 

 the cheek and the angle of the mouth as far as the lips. 



According to Jolyet and Laffont it contains besides, probably in the last 

 instance derived from the sympathetic, vasomotors for the mucous membrane of 

 the cheek and the lower lip, and their mucous glands. 



As after division of the trigeminus this region of the mucous membrane 

 becomes ulcerated, it has been thought that the buccinator contains also trophic 

 fibers. Rollet, however, called attention to the fact that section of the third 

 division causes paralysis of the muscles of mastication on the same side, and as 

 a result the teeth do not come in vertical apposition, but are pushed against the 

 cheek. In addition, in consequence of the anesthesia in the mouth, remnants of 

 food, often insufficiently comminuted, remain in contact with the cheeks, and 

 irritate the mucous membrane both mechanically and, as a result of decomposi- 



