138 



Cranial Nerves. 



GAN&L. 



C-ENICULi 



Carol int. 



GAN&L. PETROS. 

 FLEX. CAROT. 



482, The Xerve of Jacobson in the Tympanic Cavity. 



(Enlarged.) 



Tlie ninth cranial nerve is the 

 g 1 o s s o - p h a r y n g e a 1 nerve, Nermts 

 ylosso-pharyngeus. It passes through the jugular 

 foramen in a separate sheath of the dura mater 

 a nd f ( >rms h ere the j n g u 1 a r g a 11 g 1 i o n , 

 Ganglion jugulare, which is not constant; 

 in the Fosaitla petrosa of the petrous bone is 

 the p e t r o u s g a n g 1 i o n. Ganglion pelroanm, 

 always present, which communicates with the . 

 sympathetic nerve and the auricular branch 

 of the pueumogastric. From this petrous 

 ganglion. Jacobson's nerve, the tympanic 

 branch of the ninth nerve, arises; this nerve 

 runs forwards in the tympanic cavity, in 

 a groove of the promontory, sends twigs to 

 tlie mucous membrane of the tympanic cavity 

 and to the .Eustachian tube, is united by 

 means of the Nervi carotico-tympanici with 

 tlie carotid plexus, and finally passes into 

 the small superficial petrosal nerve. 



In the neck the glosso-pharyngeal 

 nerve sends branches of communi- 

 cation to the pueumogastric nerve, to the 

 carotid plexus, and the digastric and stylo- 

 hyoid branches of the facial nerve; also pharyn- 

 geal branches to the muscles of the pharynx 

 (see Fig. 486). 



Finally the nerve gives off lingual 

 branches, which pass to the tongue and 

 supply the Amis glosso-palatinus, the tonsils, 

 the anterior surface. of the epiglottis and the 

 root of the tongue, and finally end in the 

 Papillae vallatae. 



'ami ad 

 Tub. 

 Eustacltii, 



482 a. The Tympanic 



Plexus. After E. Bischoff. 



