106 INNERVATION. [CHAP. XIX. 



the nerve where it is joined by the Vidian which comes through the 

 hiatus Fallopii, intumescentia genuformis. A question arises as to 

 the nature of this swelling; is it a ganglion, or, is it merely the re- 

 sult of the separation of the fibres of the nerve at this situation ? 

 We have failed to satisfy ourselves by microscopic examination of 

 the existence of vesicular matter in it, but we have found a large 

 number of gelatinous fibres in it, as well as of tubular fibres.* 



At this swelling the facial forms a communication by means of 

 the greater superficial petrosal nerve with Meckel's ganglion, and by 

 the lesser superficial petrosal nerve, with the otic ganglion; a third 

 branch less constant than these two, is distributed to vessels and 

 dura mater on the surface of the petrous bone. As it lies in the 

 aqueduct of Fallopius, the facial nerve gives off the following 

 branches. 1. A branch to the membrane of the fenestra oval is. 

 2. A twig to the stapedius muscle. 3. The chorda tympani. 

 4. An anastomotic twig with the auricular branch of the vagus 

 nerve. 



The third stage commences at the stylo- mastoid foramen; here 

 the nerve passes obliquely through the parotid gland, in the sub- 

 stance of which it divides into its terminal branches. Immediately 

 on its emergence from the stylo -mastoid foramen,it gives off: 1. The 

 posterior auricular, or auriculo -occipital, distributed to the small 

 muscles of the ear, and the occipital muscle. 2. The stylo-liyoid 

 branch to the stylo-hyoid muscle. 3. The submastoid branch to the 

 digastric muscle. And lastly, it divides into two branches, the 

 cervico- facial, distributed to the platysma, and to the muscles of the 

 lower lip and chin, and the temporo-facial, which is distributed to 

 the orbicular muscle of the eyelids, the corrugator supercilii,aiid the 

 muscles of the nose and upper lip. The plexiform distribution of 

 these nerves on the face forms the well-known pes anserinus. The 

 facial nerve anastomoses freely with the superficial temporal, fron- 

 tal, infra-orbital, buccal and mental branches of the fifth pair, and 

 with branches of the cervical plexus. 



Function of the Facial Nerve. Referring to the anatomy of this 

 nerve, we find it distributed by the vast majority of its fibres to 

 muscles, and those minute branches, respecting the ultimate destina- 

 tion of which some doubt exists, may be, and probably are, distri- 

 buted to muscular fibres. The muscles which are supplied by the 

 facial nerve are chiefly those upon which the aspect of the countenance 

 and the balance of the features depends. The power of closing the 



* Morganti has lately published an elaborate paper, in which he maintains 

 the ganglionic character of this swelling. Annali Univ. di Medicina, 1845. 



