THE NERVOUS SYSTEM. 313 



and inner wall of tympanum; exit f stylo-mastoid foramen; dis- 

 tribution, to muscles of expression, buccinator, and platysma, 

 posterior belly of digastric, stylo-hyoid, attrahens and retrahens 

 aurem muscles, to laxator tympani and stapedius through tym- 

 panic branch, dorsal surface of tongue through chorda tympani, 

 and levator palati, and azygos uvula3 muscles through Vidian. In 

 its course through the temporal bone it communicates with many 

 important nerves; in the internal auditory meatus, w^ith audi- 

 tory; in aquaeductus Fallopii, with otic ganglion, by the small 

 petrosal; Meckel's ganglion, by the large petrosal nerve; the 

 sympathetic of the great meningeal, by the external petrosal 

 nerve; and at its exit from the stylo-mastoid foramen, with the 

 glosso-pharyngeal, pneumogastric, auriculo-temporal, auricularis 

 magnus, and the carotid plexus. Its branches are : 



On the Face. 



( Temporal, 



^ S f Temporo-facial, -| Molar, 



( Infraorbital. 



JM Aquceductus Fallopii. 



Tympanic, '| | 



Chorda tympani. , Inframaxillary> 



{Buccal, 

 Supramaxillary, 

 Inframaxillary. 



Posterior auricular, 



Stylo-hyoid, 



Digastric. 



8. AUDITORY, special nerve of hearing, consists of two por- 

 tions (1) cochlear, or auditory portion, and (2) vestibular, or 

 fibres whose function is to localize position. 



The former pass from the cochlea to the (1) accessory 

 auditory nucleus in the medulla, and. (2) to the lateral acoustic 

 tubercle in the medulla. These fibres, by means of the lateral 

 fillet, communicate with the inferior corpora quadrigemina. 



The vestibular fibres pass from the vestibule to the external 

 and internal dorsal nuclei in the floor of the fourth ventricle, 

 and by the sensory decussation to the nucleus cuneatus. 



Superficial origin, from groove between olivary and restiform 

 bodies ; course, winds around restiform body, and passes forward 

 to internal auditory meatus, with the facial; distribution, to in- 

 ternal ear by two branches : 



Vestibular, and Cochlear (vide Ear, p. 370). 



9. GLOSSO-PHARYNGEAL, or ninth, nerve of motion, common 

 sensation, and taste ; superficial origin, from medulla oblongata, 

 between olivary and restiform bodies; deep origin, from motor 



