FIFTH PAIR OF NERVES. 



297 



Vidian passes into the interior of the packet, 

 crossing its fasciculi nearly at right angles, but 

 rather in a reflex direction, and then spreads out 

 and breaks up into a number of very delicate fila- 

 ments with which cineritious matter is inter- 

 mixed, and thus a ganglionic structure is pro- 

 duced, which is in some instances more mani- 

 fest than in others, and is at the same time 

 connected with fasciculi of the facial nerve. 

 The filaments into which the Vidian separates 

 can be followed in both directions, some re- 

 trograde, and some along with the facial : 

 the former appear to pass partly to the auditory 

 nerve, as stated by Arnold, and partly to the 

 facial between the point at which the Vidian 

 joins it and the brain : they can be rent from 

 the one into the other, and indeed look more 

 like filaments from the facial to the Vidian than 

 from the latter to the former. The latter fila- 

 ments of the Vidian are dispersed among the 

 fasciculi of the facial, with which they become 

 united, and can be followed by means of a 

 careful dissection for some distance : their 

 number the writer is not prepared to state : the 

 fasciculus of the facial from which the chorda 

 tympani more particularly arises, appears deci- 

 dedly to receive one or it may be more. Fur- 

 ther, the chorda tympani does not arise by a 

 single root, but is formed by two or three de- 

 rived from different parts of the facial. The 

 opinion that the chorda tympani is a continu- 

 ation of the Vidian nerve appears, therefore, to 

 the writer altogether unfounded, and while he 

 admits that the conclusion of Arnold may proba- 

 bly be well-founded, with regard to its compound 

 nature, he yet must dissent from the opinion that 

 the branch which forms it arises immediately 

 from the gangliform swelling of the facial the 

 fasciculus, from which its principal root pro- 

 ceeds, existing distinctly upon both sides of, 

 and consequently not arising from the swelling, 

 however it may receive an accession from, or be 

 affected by its connection with this part. The 

 author cannot refrain from regarding the chord 

 as a branch of the facial nerve in the same sense 

 with any other branch arising within the limits 

 of the influence of the Vidian nerve. Magendie 

 maintains that the chord is a continuation of 

 the Vidian, because the section of the fifth nerve 

 itself deprives the ear of all sensibility, but 

 whatever part the chord may play in the sensi- 

 bility of the ear, and it is doubtful that it plays 

 any, the result of the experiment will be easily 

 explained by the doctrine of Eschricht, that 

 the facial nerve owes its sensibility to the fifth 

 nerve, the division of which must in such case 

 influence through the Vidian nerve any branch 

 of the facial arising within the range of its in- 

 fluence. 



After the junction of the chorda tympani 

 with the lingual branch, the latter gives at times 

 a small branch to the internal pterygoid mus- 

 cle : during its descent along the ramus of the 

 jaw, it also^ gives filaments to the arches of the 

 palate, to the mucous membrane of the cheek, 

 and to the gum of the lower jaw. While the 

 nerve is situate between the mucous membrane 

 of the mouth and the submaxillary gland, it is 

 connected by means of two, three, or four fila- 



ments with the submaxillary ganglion. This 

 ganglion is a small reddish body resembling the 

 spheno-palatme ganglion in size, colour, and 

 consistence, situate above the posterior extre- 

 mity of the submaxillary gland, and connected 

 superiorly with the lingual branch by the fila- 

 ments mentioned ; inferiorly there arises from 

 it a considerable number of very delicate nerves, 

 which descend through the divisions of the 

 gland, anastomose with each other, and are 

 distributed for the most part to the substance 

 of the gland ; one of them descends upon the 

 hyoglossus, anastomoses with a filament from 

 the ninth, and enters into the genioglossus 

 muscle, and another long one accompanies the 

 duct of the gland. A filament of communi- 

 cation also from the superior cervical ganglion 

 of the sympathetic reaches the submaxillary 

 ganglion by following the course of the facial 

 artery, and is represented by Arnold. 



The filaments by which the ganglion is con- 

 nected to the lingual branch, are, as has been 

 stated, two, three, or four ; they are not attached 

 to the nerve all together, but one or two some 

 lines before the others, and they are remarkable 

 for the circumstance, that the posterior descend 

 forward, while the anterior descend backward ; 

 on attentive examination it is found that the 

 posterior are derived one from the chorda tym- 

 pani, and the other from the lingual branch 

 itself; it also appears that the filament derived 

 from the former source is but a part of the cord, 

 the remainder being continued on with the 

 trunk of the lingual, and again that the anterior 

 filament or filaments, which descend backward 

 to the ganglion, are continuations of the poste- 

 rior, which, after having been connected to the 

 ganglion, ascend forward from it again to the 

 trunk of the nerve. The course of those fila- 

 ments of connection is well described and re- 

 presented by the elder Meckel, and a very accu- 

 rate delineation of them is given by Treviranus 

 and Arnold. To this connection probably it 

 is, that we are to attribute the influence which 

 impressions on the organs of taste, or even 

 sounds exert upon the salivary apparatus ; let 

 us, when hungry, only hear a sound associated 

 in our minds, in any way, with the gratification 

 of our appetite, and at once that apparatus is 

 roused into activity. 



Next, while lying between the mylohyoid and 

 the hyoglossus muscles, the lingual nerve sends 

 off from its inferior side some branches, which 

 descend upon the hyoglossus, and anastomose 

 with filaments ascending from the ninth nerve. 

 At the same time, from its superior side, it 

 gives filaments ; some of which, the posterior, 

 are distributed to the mucous membrane and 

 to the gum of the lower jaw ; others, the ante- 

 rior, to the sublingual gland, and by some of 

 their ramifications to the membrane and the 

 gum. Lastly, the nerve divides at the anterior 

 margin of the hyoglossus into its lingual 

 branches ; these are, at first, three, poste- 

 rior, middle, and anterior ; they pass up- 

 ward and forward^ and divide, each into 

 two or three branches, which altogether di- 

 verge from the nerve, and are ranged in suc- 

 cession from behind forward, along the line 



