THE SEVENTH OR FACIAL NERVE 



999 



then bends suddenly backward and arches downward behind the tympanum 

 to the stylomastoid foramen. At the point in the aqueduct of Fallopius where the 

 nerve changes its direction (geniculum n. facialis), it presents a reddish, gangli- 

 form swelling, the geniculate ganglion (ganglion genicidi} or intumescentia ganglio- 

 formis (Fig. 739). The geniculate ganglion receives a branch from the vestibular 

 division of the auditory nerve. On emerging from the stylomastoid foramen 

 the facial nerve runs forward in the substance of the parotid gland, crosses the 

 external carotid artery, and divides behind the ramus of the mandible into two 

 primary branches, temporofacial and cervico facial, from which numerous offshoots 

 are distributed over the side of the head, face, and upper part of the neck, supply- 

 ing the superficial muscles in these regions. As the primary branches and their 

 offshoots diverge from each other, they present somewhat the appearance of a 

 bird's claw; hence the name of pes anserinus is given to the divisions of the facial 

 nerve in and near the parotid gland. 



Branches of Communication (Fig. 740). The communications of the facial 

 nerve may be thus arranged : 



fWith the acoustic nerve. The nervus 

 intermedius, which is between the 

 facial and acoustic, is supposed to give 

 branches to both. The branch given 

 to the acoustic accompanies it for a 

 certain distance, and then departs 

 from it to join the geniculate ganglion. 

 With the acoustic as explained above. 

 With the sphenopalatine ganglion by 



the large superficial petrosal nerve. 

 With the otic ganglion by the small 



superficial petrosal nerve. 

 With the sympathetic on the middle 

 meningeal artery by the external super- 

 ficial petrosal nerve. 



With the auricular branch of the vagus. 



In the internal auditory meatus 



From the geniculate ganglion 



In the canalis facialis or Fallopian ) 

 aqueduct J 



At its exit from the stylomastoid 

 foramen . 



Behind the ear 



On the face 



In the neck . 



With the glossopharyngeal. 



With the vagus. 



With the great auricular. 



With the auriculotemporal. 



With the small occipital. 



With three divisions of the trigeminal. 



With the superficial cervical. 



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

 and acoustic nerves. 



The large superficial petrosal nerve arises from the geniculate ganglion and con- 

 sists chiefly of sensor branches which are distributed to the mucous membrane 

 of the soft palate. It probably also contains a few motor fibres which form the 

 motor root of the sphenopalatine (Meckel's) ganglion. It passes forward through 

 the hiatus canalis facialis (Fallopii) and runs in a groove on the anterior surface 

 of the petrous portion of the temporal bone beneath the Gasserian ganglion to 

 the foramen lacerum medium. It receives a twig from the tympanic plexus, 

 and in the foramen is joined by the great deep petrosal, from the sympathetic 

 plexus on the internal carotid artery, to form the Vidian, nerve. This nerve passes 

 through the Vidian canal and ends in the sphenopalatine (Meckel's) ganglion. 

 The geniculate ganglion is connected with the otic ganglion by a branch which 



