NINTH PAIR GLOSSO PHARYNGEAL. 499 



to form the auricular plexus. It gives twigs to the anterior 

 auricular muscles; to the orbicularis palpebrarum, and levator 

 palpebrae superioris externus. The posterior auricular nerve 

 passes upwards with the posterior auricular artery, and supplies 

 the posterior muscles of the ear and the skin. The middle auri- 

 cular nerve enters the concha, to the inner surface and cartilage 

 of which it is distributed. 



The terminal or temporo-facial branches of the facial nerve 

 are in two sets ; an inferior, which passes downwards to the 

 lower lip and muscles of the side of the cheek and lower jaw ; and 

 a superior, which supplies the muscles of the nose and tissues of 

 the upper lip. They-communicate with the terminal branches of 

 the superior and inferior maxillary divisions of the fifth nerve, 

 and, from the peculiar looped and radiate manner of their termi- 

 nations, have obtained the name of pea anserinus. 



EIGHTH PAIR PORTIO MOLLIS, OR AUDITORY. 



The nerve of the special sense of hearing has its origin on the 

 medulla oblongata, close to the facial nerve. Its deep roots are 

 anterior and posterior, the one springing from the central grey 

 matter of the medulla, and the other from the floor of the fourth 

 ventricle. The auditory nerve enters the meatus auditorius 

 internus in company with the seventh, and at the bottom of the 

 passage divides into two branches ; an anterior or cochlear, dis- 

 tributed to the cochlea, and a posterior or vestibular, which 

 supplies the vestibule and the remaining portions of the internal 

 ear. 



NINTH PAIR GLOSSO-PHARYNGEAL. 



This is a mixed nerve, principally distributed to the tongue 

 and pharynx, and it arises from the medulla, the fibres composing 

 it being traceable to the restiform bodies and the olivary fasciculi. 

 It pierces the dura mater through a distinct opening, and leaves 

 the cranium through the foramen lacerum basis cranii; pre- 

 viously however presenting a gangliform swelling, the petrosal or 

 Andersch's ganglion, which rests on the petrosal bone. Leaving 

 the cranium, it passes downwards and forwards, between the 

 guttural pouch and pterygoid muscles, and along the posterior 

 border of the cornu of the os hyoides, to gain the base of the 

 tongue, being distributed to the mucous membrane and substance, 

 principally of the base and sides of that organ. 



