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 rams 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. NN bile 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 lila tnents 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 of separation between the stylo-glossus and the genio-glossus ; they traverse the substance of the tongue toward its superior surface and mar gin, and run along its inferior surface, above the mucous membrane, toward its extremity ; as they proceed they subdivide, and thus re sults a great number of filaments, the course of which through the tongue is remarkable ; they appear not to terminate, any of them, in the substance of it, but they traverse it as long, slender, single filaments, unconnected with its structure until they approach its superior sur face, when they break up into pencils (to adopt the phrase used) of still more delicate filaments, which may be followed into the mu cous membrane; the posterior filaments of the posterior branch insinuate themselves internal to the liyoglossus, and reach as far back as the foramen ccecum ; the filaments of the anterior are distributed to the extremity of the tongue, and are continued between the under surface of it and the mucous membrane very near to the tip, the substance of which they then tra verse in order to reach its superior aspect and margin : they thus supply the mucous mem brane of the organ upon its superior and lateral parts, from the foramen ccecum to its point.
Ganglion of the fifth nerve (Ganglion semilunare Gasseri). See fig. 140, 9.— The ganglion of the fifth nerve is a body of crescentic form, a cineritious colour, and firm consistence. It presents two surfaces, two margins, and two extremities : its surfaces are both slightly pro minent, and are directed one upward, outward, and forward, the other downward, inward, and backward ; they are also, the former con cave and the latter convex longitudinally, the ganglion being somewhat curved upon itself in the same direction : they are both for the most part adherent to the lamina' of dura mater, which form the chamber in which the gan glion is contained ; but it is not uncommon to find the arachnoid membrane prolonged beneath it, so that its inferior surface in such instances is free; the superior corresponds to the cranial cavity in its middle fossa, being excluded from it only by the dura mater; • the inferior rests, with the intervention of dura mater also, upon the petrous portion of the temporal bone, the great ala of the sphenoid, and against the outer side of the cavernous sinus. The margins of the ganglion are di rected one forward and downward, the other backward and upward ; the anterior is convex, and to it are attached the three great trunks, which compose the ganglionic portion of the nerve in its third stage ; the posterior is con cave and presents through its entire length a deep groove, into which the fasciculi of the ganglionic packet of the nerve are received. The extremities arc obtuse, and project beyond the packet at either side; they are situate re latively, one superior, internal, and anterior to the other. When the ganglion is in situ, the chord of the arch which it forms is six or seven lines long ; Niemeyer has sometimes found it amount to from nine to ten:* its width is about two lines, and Its thickness, according to the part, from half a line to a line. Its colour and appearance vary much according to the subject : the former is always of a cine ritious tint of different degrees of intensity ; when the subject is wasted, flabby, or anasar cous, it is pale or grey, while, if the subject have been robust and corpulent, it is of a deep brown colour : in the former case also a plexi form arrangement is more perceptible, whereas in the latter the ganglion seems composed of two concentric arcs, an anterior of lighter colour and manifestly plexiform character, and a posterior of very deep colour and apparently homogeneous indeterminate texture, devoid al together of the plexiform appearance.