404 GLOSSO-PHARYNGEAL NERVE. 



auditorius internus, and at the bottom of the meatus it divides into twa 

 branches, cochlear and vestibular. The auditory nerve is soft and pulpy 

 in texture, and receives in the meatus auditorius several filaments from the 

 facial nerve. 



EIGHTH PAIR. The eighth pair consists of three nerves, glosso- 

 pharyngeal, pneumogastric, and spinal accessory ; these are the ninth 

 tenth, and eleventh pairs of Soernmering. 



GLOSSO-PHARYNGEAL NERVE. The glosso-pharyngeal nerve arises by 

 five or six filaments from the groove between the corpus olivare and resti 

 forme, and escapes from the skull at the innermost extremity of the jugular 

 foramen through a distinct opening in the dura mater, lying anteriorly to 

 the sheath of the pneumogastric and spinal accessory nerves, and internally 

 to the jugular vein. It then passes forwards between the jugular vein and 

 internal carotid artery, to the stylo-pharyngeus muscle, and descends 

 along the inferior border of that muscle to the hyo-glossus, beneath which 

 it curves to be distributed to the mucous membrane of the base of the 

 tongue and fauces, to the mucous glands of the mouth, and to the tonsils. 

 While situated in the jugular fossa, the nerve presents two gangliform 

 swellings ; one superior (ganglion jugulare of Miiller) of small size, and 

 involving only the posterior fibres of the nerve ; the other inferior, nearly 

 half an inch below r the preceding, of larger size and occupying the whole 

 diameter of the nerve, the ganglion of Andersen* (ganglion petrosum). 



The fibres of origin of this nerve may be traced through the fasciculi 

 of the corpus restiforme to the grey substance in the floor of the fourth 

 ventricle. 



The Branches of the glosso-pharyngeal nerve are 



Communicating branches with the Facial, 



Pneumogastric, 

 Spinal accessory, 

 Sympathetic. 



Tympanic, 



Muscular, 



Pharyngeal, 



Lingual, 



Tonsillitic. 



The Branches of communication proceed from the ganglion and from 

 the upper part of the trunk of the nerve, and are common to the facial, 

 eighth pair, and sympathetic ; they form a complicated plexus at the base 

 of the skull. 



The Tympanic branch (Jacobson's nerve) proceeds from the ganglion 

 of Andersch, or from the trunk of the nerve immediately above the gan- 

 glion : it enters a small bony canal in the jugular fossa (page 68) and 

 divides into six branches, winch are distributed upon the inner w r all of the 

 tympanum, and establish a plexiform communication (tympanic plexus) 

 with the sympathetic and fifth pair of nerves. The branches of distribu- 

 tion supply the fenestra rotunda, fenestra ovalis, and Eustachian tube : 

 those of communication join the carotid plexus, the petrosal branch of the 

 Vidian nerve, and the otic ganglion. 



* Charles Samuel Andersch. Tractatus Anatomico-Physiologicus de Nervis Cor 

 poris Humani Aliquibus. 1797." 



