293 



FIFTH PAIR OF NERVES. 



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 hyoglossus, 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 caecum to its point. 



Ganglion of the fijtk nerve (Ganglion 

 scmilunure Gasserl). See Jig. 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 laminae 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 are 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 



* DC ortgiue paris quiuti nervorum cerebri mono- 

 graphia. Hale, 1812. 



is about two lines, and its thickness, according 

 to the part, from half a line to a line. Its 

 colour and appearance rary 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. 



A particular inquiry into the structure and 

 probable function of the ganglion of the fifth 

 nerve would involve that of the cerebro-spinal 

 ganglia in general, and will be better post- 

 poned to another occasion : it will suffice for 

 the present to state that according to both 

 Monro and Scarpa, they are composed in 

 part of nervous chords, and in part by a 

 soft grey or brown substance, which fills 

 the intervals between the nervous filaments, 

 and which according to the former resembles 

 the cortical matter of the brain, while in the 

 opinion of the latter it is a cellular texture 

 filled by a matter, which varies in character 

 according to the subject; thus he states that he 

 has found it fatty in fat and watery in anasar- 

 cous subjects. 2. That nervous filaments can 

 be traced through them without interruption 

 from the nerves situate above to those situate 

 below the ganglion, which opinion is objected 

 to by Niemeyer, who compares the connection 

 of the former with the ganglion to that of the 

 fcetal and maternal portions of the placenta ; 

 but inspection suffices to satisfy one that this 

 idea of Niemeyer is incorrect; for whether 

 additional filaments be furnished or not by the 

 ganglion, the continuity of filaments above 

 and below it is evident even in the human 

 subject, and is still more manifest in other 

 animals : in the horse it is easily seen, par- 

 ticularly after a section of the ganglion. 



The question whether the ganglion receives 

 filaments from the sympathetic system has 

 been a subject of dispute among anatomists. 

 The elder Meckel* denies the existence of any 

 filaments of connection between the sympa- 

 thetic and the fifth nerve, while within the 

 fibrous chamber or while situate by the cavern- 

 ous sinus; and others also, among whom are 

 Eustachius, Ilaller, Albinus, and Morgagni, 

 are of the same opinion ; but later investiga- 

 tions have put it beyond doubt that such a 

 communication does exist. Bock-)- has de- 

 scribed filaments of the sympathetic united to 

 the trunk of the fifth, before the formation of 

 the Gasserian ganglion, and which join chiefly 

 the fasciculi of the trunk, from which the 

 ophthalmic nerve originates. And Arnold 



Mini 



* Scrtptores Neurologic! Minorca, torn. i. 



t Beschreihung dcs funftcn Ncrvenpaarcs un 

 seiner Veibindung mit andcrn Nerven, vorzuglich 

 mil dcm Gangliensystem, 1817. 



