FACIAL. 611 



the internal auditory meatus with the auditory nerve. Within the raeatus, the 

 facial nerve lies first to the inner side of the auditory, and then in a groove upon 

 that nerve, and is connected to it by one or two filaments. 



At the bottom of the meatus, it enters the aquaeductus Fallopii, and follows 

 the serpentine course of that canal through the petrous portion of the temporal 

 bone, from its commencement at the internal meatus to its termination at the 

 stylo-mastoid foramen. It is at first directed outwards towards the hiatus Fal- 

 lopii, where it forms a reddish gangliform swelling (intumescentia ganglioformis), 

 and is joined by several nerves ; then bending suddenly backwards, it runs in 

 the internal wall of the tympanum, above the fenestra ovalis, and at the back 

 of that cavity passes vertically downwards to the stylo-mastoid foramen. 



On emerging from this aperture, it runs forwards in the substance of the 

 parotid gland, crosses the external carotid artery, and divides behind the ramus 

 of the lower jaw into two primary branches, temporo-facial and cervico-facial, 

 from which numerous offsets are distributed over the side of the head, face, 

 and upper part of the neck, supplying the superficial muscles in these regions. 

 As the primary branches and their offsets diverge from each other, they present 

 somewhat the appearance of a bird's claws ; hence the name of pes anserinus is 

 given to the divisions of the facial nerve in and near the parotid gland. 



The communications of the facial nerve may be thus arranged : 



In the internal auditory meatus . With the auditory nerve. 



f With Meckel's ganglion by the large 



petrosal nerve. 



With the otic ganglion by the small 

 In the aquasductus Fallopii . { petrosal nerve. 



With the sympathetic on the middle 

 meningeal by the external petrosal 

 nerve. 

 With the pneumogastric. 



At its exit from the stylo-mastoid 

 foramen . 



glosso-pharyngeal. 

 carotid plexus. 



auricularis magnus. 

 " auriculo-temporal. 

 On the face .... With the three divisions of the fifth. 



In the internal auditory meatus, some minute filaments pass between the 

 facial and auditory nerves. 



Opposite the hiatus Fallopii, the gangliform enlargement on the facial nerve 

 communicates by means of the large petrosal nerve, with Meckel's ganglion, 

 forming its motor root ; by a filament from the small petrosal, with the otic 

 ganglion ; and by the external petrosal, with the sympathetic filaments accom- 

 panying the middle meningeal artery (Bidder). From the gangliform enlarge- 

 ment, according to Arnold, a twig is sent back to the auditory nerve. 



At its exit from the stylo-mastoid foramen, it sends a twig to the pneumo- 

 gastric, another to the glosso-pharyngeal nerve, and communicates with the 

 carotid plexus of the sympathetic, with the great auricular branch of the cer- 

 vical plexus, with the auriculo-temporal branch of the inferior maxillary nerve 

 in the parotid gland, and on the face with the terminal branches of the three 

 divisions of the fifth. 



i 

 BRANCHES OF DISTRIBUTION. 



AVithin aquseductus Fallopii 7 m an . c - 



( Chorda tympani. 



.t exit fr 

 foramen 



At exit from stylo-mastoid P steri ? r auricular. 



foramen 1 Digastric. 



' ( Stylo-hyoid. 



