GLOSSO-PHARYNGEAL NERVES 639 



section of the chorda tympani or of the facial so as to involve the 

 chorda tympani the sense of taste is abolished in the anterior two- 

 thirds of the tongue on the side of the section. In a number of cases 

 the introduction of an artificial membrana tympani in the human subject 

 has been followed by loss of taste on the corresponding side of the 

 tongue, and on both sides, when membranes were introduced into 

 both ears. This disappears when the membranes are removed ; and 

 the phenomena may properly be referred to pressure on the chorda 

 tympani. 



As regards the gustatory properties of the anterior two-thirds of the 

 tongue, certainly in the human subject, it may be stated without reserve 

 that these properties depend on the chorda tympani, its gustatory fila- 

 ments taking their course to the tongue with the lingual branch of the 

 inferior maxillary division of the fifth. In addition, the lingual branch 

 of the fifth contains filaments derived from the large root of this nerve, 

 which give general sensibility to the mucous membrane. 



GLOSSO-PHARYNGEAL (NINTH NERVE) 



The gtosso-pharyngeal is distributed to those portions of the gusta- 

 tory mucous membrane not supplied by filaments from the chorda 

 tympani. It undoubtedly is a nerve of taste ; and the question of its 

 other uses will be considered in connection with its general proper- 

 ties, as well as the differences between this nerve and the chorda 

 tympani. 



Physiological Anatomy. The apparent origin of the glosso-pharyn- 

 geal is from the groove between the olivary and restiform bodies of the 

 medulla oblongata, between the roots of the auditory nerve above and 

 the pneumogastric below. The deep origin is in a gray nucleus in the 

 lower part of the floor of the fourth ventricle, between the nucleus of 

 the auditory nerve and the nucleus of the pneumogastric. From this 

 origin, the nerve passes forward and outward, to the posterior foramen 

 lacerum, by which it emerges with the pneumogastric, the spinal acces- 

 sory and the internal jugular vein. At the upper part of the fora- 

 men, is a small ganglion, the jugular ganglion, including only a portion 

 of the root. Within the foramen, is the main ganglion, including all 

 the filaments of the trunk, called the petrous ganglion, or the ganglion 

 of Andersch. 



At or near the ganglion of Andersch the glosso-pharyngeal usually 

 receives a small filament from the pneumogastric. This communication 

 is sometimes wanting. The same may be said of a filament passing to 

 the glosso-pharyngeal from the facial, which is not constant. Branches 



