5io 



NERVOUS SYSTEM 



bones of the ear and through the tympanic cavity to the lingual branch 

 of the inferior maxillary division of the fifth, which it joins at an acute 

 angle, between the pterygoid muscles. As regards the portion of the 

 facial that furnishes the filaments of the chorda tympani, it is nearly 

 certain that these come from the intermediary nerve of Wrisberg. 



There can be no doubt in regard to the influence of the chorda 

 tympani on the sense of taste in the anterior two-thirds of the tongue. 

 In cases of disease or injury in which the root of the facial is involved 

 so that the chorda tympani is paralyzed, in addition to the ordinary 

 phenomena of paralysis of the superficial muscles of the face, there is 



loss of taste in the anterior two- 

 thirds of the tongue on the side 

 corresponding to the lesion. The 

 action of the chorda tympani will 

 be considered again, in connec- 

 tion with the physiology of gus- 

 tation. 



Influence of Certain Branches 

 of the Facial on the Movements 

 of the Palate and Uvula. 

 There can be little doubt that 

 filaments from the facial animate 

 certain of the movements of the 

 velum palati and the uvula. It 

 has been observed that in cer- 

 tain cases of facial paralysis the 

 palate on one side is flaccid and 

 the uvula is drawn to the opposite 

 side ; but these phenomena do not occur unless the nerve is affected 

 at its root or within the aquaeductus Fallopii. It is true that the 

 uvula frequently is drawn to one side or the other in persons unaffected 

 with facial paralysis, but it is none the less certain that it is deviated 

 as a consequence of paralysis of the facial in some instances. The 

 filaments of the facial which influence the levator palati and azygos 

 uvulae muscles are derived from the large petrosal branch of the nerve, 

 passing to the muscles through Meckel's ganglion, the filaments to the 

 palato-glossus and the palato-pharyngeus being given off from the 

 glosso-pharyngeal, but originally coming from an anastomosing branch 

 of the facial. 



In view of examples of paralysis of the palate and uvula in certain 

 cases of facial palsy, the frequent occurrence of contractions of the 

 muscles of these parts following stimulation of the facial and the reflex 



Fig. 123. Chorda-tympani nerve (Hirschfeld). 



i, 2, 3, 4, facial nerve passing through the 

 aquaeductus Fallopii; 5, ganglioform enlargement 

 (geniculate ganglion); 6, great petrosal nerve; 

 7, spheno-palatine ganglion ; 8, small petrosal nerve ; 

 9, chorda tympani; 10, n, 12, 13, various branches 

 of the facial ; 14, 14, 15, glosso-pharyngeal nerve. 



