764 THE XER VOL'S SYSTEM 



external aiulitorv meatus and tlie mastoid proeess. In this situation it eonmiuni- 

 cates with the auricular branch of tlie pneumogastric. It supplies the retraliens 

 aurem, and sends a slender twig upwards to the attollens aurem, and ends in a long 

 slender branch, Avhich passes backwards to sui)plythe ])ostcrior belly of the occipito- 

 frontalis. It also receives filaments from the small occipital and ])osterior auricular 

 nerves, and supplies the oblique and transverse muscles on the inner surface of 

 the pinna. 



(6) The nerve to the posterior belly of the digastric arises from the facial 

 nerve close to the stylo-mastoid foramen, and enters the digastric near the centre of 

 that muscle, or sometimes near its origin. It frequently communicates with the 

 glosso-pharyngeal nerve. 



(c) The nerve to the stylo-hyoid arises at the same level as the preceding 

 nerve, the two nerves sometimes forming a common trunk. It ends in the upper 

 part of the muscle for which it is destined. 



The lingual branch is remarkable fur its lung course. It arises close to the two small muscular 

 uerves above described. It pa.sses ou the outer side of the stj'lo-pharj-ngeus muscle, and gains 

 the side of the phar3'nx. In this situation it is joined by filaments from the glosso-pharyngeal. 

 It then passes between the palato-glossus muscle and the tonsil, and reaches the base of the 

 tongue, where it ends in filaments to the mucous membrane and in twigs to the palato-glossus 

 and stylo-glossus muscles. (Testut.) 



(3) Six branches are given off from the two terminal divisions of the facial 

 nerve. These branches traverse the substance of the jjarotid gland, and emerge at 

 its margin. At their emergence they range from a point on the zygoma, a little in 

 front of the spot where the temporal artery crosses the bone, to the angle of the 

 lower jaw. These branches proceed forwards over the face and front of the neck, 

 and by frequently communicating with one another form a great expanded plexus 

 which is called the pes anserinus. Taken in order from above downAvards, the 

 temporo-facial division gives off the following branches: temporal, malar, and 

 infraorbital. The cervico-facial division divides into buccal, supra-mandilndar and 

 infra-mandibular branches. 



The TEMPORO-FACIAL DIVISION of the facial nerve runs obliquely upAvards 

 and forwards through the substance of the parotid gland, crosses the external carotid 

 artery and the temporo-maxillary vein on the superficial aspect of those vessels, and 

 terminates, as above described, in three branches. 



In this course it receives communications from the auriculo-temporal nerve, as 

 mentioned in the description of the fifth nerve. 



(a) The temporal branch passes upwards through the parotid gland, and 

 emerges at the upper border of the gland at a point a little in front of the temporal 

 artery. It divides into several branches, which communicate with one another and 

 with the malar branch.- It also communicates with the temporal branch of the 

 orbital, and with the supraorbital nerve. Its largest l)ranches are distributed to the 

 upper part of the orbicularis palpebrarum, and to the anterior belly of the occijnto- 

 frontalis. It also supi3lies the attrahens aurem, th(^ corrugator supercilii, and, 

 occasionally, the attollens aurem. 



The fibres which run in the facial nerve to end in the orbicularis palpebrarum, the cornigator 

 supercilii, and the frontalis muscles are probably derived from the oculo-motor nucleus of the same 

 side, and pass downwards in the posterior longitudinal bundle to ioin the genu nervi facialis. 

 (Mendel.) 



(b) The malar branch is a smaller neiwe than the preceding. It is directed 

 upwards and forwards to reach the most prominent part of the malar bone; it 

 supplies the lower part of the orbicularis palpebrarum. It also gives twigs to both 

 eyelids; it communicates with the malar branch of the orbital, Avith the supra- 

 orbital and lachrymal branches of the ophthalmic, with the palpebral tAvigs derived 

 from the superior maxillary division of the fiftli. and witli the temporal and infra- 

 orbital branches of the facial. 



{(•) The infraorbital is the largest of the nerves which enter into the })es anser- 

 inus. It escajies from the })arotid gland above Stenson's duct, and diA'ides into 

 seA'eral branches. These branches comii)uni<'ate freely with one another, and ]>ass 



