, 



448 GLOSSO-PHARYNGEAL NERVE. 



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

 restiforme, and escapes from the skull at the innermost extremity of the 

 jugular foramen through a distinct opening in the dura mater, lying an- 

 teriorly 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 ganglifonn swellings ; one superior (ganglion 

 jugulare ofMiiller) of small size, and involving only the posterior fibres 

 of the nerve; the other inferior., nearly half an inch below the prece- 

 ding, of larger size and occupying the whole diameter of the nerve, 

 the ganglion of Andersch* (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 

 ganglion: it enters a small bony canal in the jugular fossa (page 34) 

 and divides into six branches, which are distributed upon the inner 

 wall of the tympanum, and establish a plexiform communication (tym- 

 panic plexus) with the sympathetic and fifth pair of nerves. The 

 branches of distribution 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 deNervis 

 Corporis Huraani Aliquibus, 1/9/." 



