402 FACIAL NERVE. 



crus cerebelli, and comes into relation with the auditory nerve, with which 

 it enters the meatus auditorius internus, lying at first to the inner side of, 

 and then upon that nerve. At the bottom of the meatus it enters the canal 

 expressly intended for it, the aqueductus Fallopii, and directs its course 

 forwards towards the hiatus Fallopii, where it forms a gangliform swelling 

 (intumescentia gangliformis), and receives the petrosal branch of the Vidian 

 nerve. It then curves backwards towards the tympanum, and descends 

 along the inner wall of that cavity to the stylo-mastoid foramen. Emerg- 

 ing at the stylo-mastoid foramen it passes forwards within the parotid 

 gland, crossing the external jugular vein and external carotid artery, and 

 at the ramus of the lower jaw divides into two trunks, temporo-facial and 

 cervico-facial. These trunks at once split into numerous branches, which, 

 after forming a number of looped communications (pes anserinus) with 

 each other over the masseter muscle, spread out upon the side of the face, 

 from the temple to the neck, to be distributed to the muscles of this exten- 

 sive region. The communications which the facial nerve maintains in its 

 course are the following: in the meatus auditorius, it sends one or two 

 filaments to the auditory nerve ; the intumescentia gangliformis receives 

 the nervus petrosus superficialis major and minor, and sends a twig back 

 to the auditory nerve ; behind the tympanum the nerve receives one or 

 two twigs from the auricular branch of the pneumogastric ; at its exit from 

 the stylo-mastoid foramen it receives a twig from the glosso-pharyngeal, 

 and in the parotid gland one or two large branches from the anterior 

 auricular nerve. Besides these, the facial nerve has numerous peripheral 

 communications, with the branches of the fifth nerve on the face, and of 

 the cervical nerves in the parotid gland and neck. The numerous com- 

 Miunications of the facial nerve obtained for it the designation of nervm 

 sympatheticus minor. 



The Branches of the facial nerve are 



Within the aqueductus ( Tympanic, 

 Fallopii, I Chorda tympani. 



aA . . ,j C Posterior auricular, 



Jlfter emerging at ^5 Stylo _ hyoid 

 stylo-mastoid foramen, ^ jjfofa 



-. ., - ( Temporo-facial, 



On the face, J Cervico-facial. 



The Tympanic branch is a small filament distributed to the stapedius 

 muscle. 



The Chorda tympani quits the facial just before that nerve emerges 

 from the stylo-mastoid foramen, and ascends by a distinct canal to the 

 upper part of the posterior wall of the tympanum, where it enters that 

 cavity through an opening situated between the base of the pyramid and 

 the attachment of the membrana tympani, and becomes invested by mu 

 f.ous membrane. It then crosses the tympanum between the handle of 

 the malleus and long process of the incus to the anterior inferior angle of 

 the cavity, and escapes through a distinct opening in the fissura Glaseri, 

 and joins the gustatory nerve at an acute angle between the two pterygoid 

 muscles. Enclosed in the sheath of the gustatory nerve, it descends to 

 lie subm axillary gland, where it unites with the subm axillary ganglion 



The Posterior auricular nerve ascends behind the ear, between the 



