GLOSSO-PHARYNGEAL NERVES. 665 



the sense of taste is abolished in the anterior two-thirds of the tongue on 

 the side of the section. In a case reported by Moos, the introduction of an 

 artificial membrana tympani in the human subject was followed by loss of 

 taste upon the corresponding side of the tongue, and upon both sides, when 

 a membrane was introduced into each ear. This disappeared when the 

 membranes were removed, and the phenomena were referred to pressure 

 upon the chorda tympani. Other instances of this kind are on record. 



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 upon the chorda tympani, its gustatory filaments 

 being derived from the facial and taking their course to the tongue with 

 the lingual branch of the inferior maxillary division of the fifth. In addi- 

 tion, the lingual branch of the fifth contains filaments, derived from the 

 large root of this nerve, which give general sensibility to the mucous mem- 

 brane. 



GLOSSO-PHARYXGEAL (NINTH NERVE). 



The glosso-pharyngeal is distributed to those portions of the gustatory 

 mucous membrane not supplied by filaments from the chorda tympani. It 

 is undoubtedly a nerve of taste ; and the question of its other uses will be 

 considered in connection with its general properties, as well as the differences 

 between this nerve and the chorda tympani. 



Physiological Anatomy. The apparent origin of the glosso-pharyngeal 

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

 oblongata, between the roots of the auditory nerve above and the pneumo- 

 gastric 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 filaments pass for- 

 ward and outward, to the posterior foramen lacerum, by which the nerve 

 emerges with the pneumogastric, the spinal accessory and the internal jugu- 

 lar vein. At the upper portion of the foramen, is a small ganglion, the 

 jugular ganglion, including only a portion of the root. Within the foramen, 

 is the main ganglion, including all of 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 delicate filament from the pneumogastric. This communication 

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

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

 the glosso-pharyngeal go to the otic ganglion and to the carotid plexus of the 

 sympathetic. 



The distribution of the glosso-pharyngeal is quite extensive. The tym- 

 panic branch, the nerve of Jacobson, arises from the anterior and external 

 part of the ganglion of Andersch, and enters the cavity of the tympanum, 

 where it divides into six branches. Of these six branches, two posterior are 

 distributed to the mucous membrane of the fenestra rotunda and the mem- 

 brane surrounding the fenestra ovalis ; two anterior are distributed, one to 



