FIFTH PAIR OF NERVES. 



285 



others ivr o or three : they are short and of con- 

 siderable size, and arise from the inferior side 

 of the nerve, immediately after it has entered 

 the spheno-maxillary fossa ; they descend from 

 it, almost perpendicularly, into the fossa, pos- 

 terior to the internal maxillary artery, and im- 

 mersed in fat, and after a very short course 

 they are connected to the ganglion, from which 

 they may seem to ascend to the nerve. They 

 are thus described by Cloquet, but this view is 

 not sanctioned either by comparative anatomy, 

 or by the result of experiments, both which 

 prove that they are to be considered branches 

 of the nerve, with which the ganglion is con- 

 nected. 



The ganglion has been first described by 

 the elder Meckel,* and hence has also received 

 the title of Meckel's ganglion ; it is very small, 

 of a grey colour, and firm consistence ; its 

 shape is triangular or cordiform, one surface 

 directed outward, the other inward; it is situate 

 immediately external to the spheno-palatine 

 foramen, its internal surface, which is flat, cor- 

 responding to the foramen, its external, which 

 is convex, to the zygomatic fossa. It is subject 

 to variety ; in some instances it is wanting, 

 and then the spheno-palatine nerve gives off 

 those branches which otherwise arise from the 

 ganglion : in other rare cases, according to 

 Meckel, the two principal branches, which 

 arise from the ganglion when present, or 

 from the spheno-palatine when single, viz. the 

 Vidian and the palatine, proceed separately from 

 the trunk of the second division of the fifth ; in 

 others again the author has observed a cineri- 

 tious soft enlargement upon the Vidian nerve 

 at its junction with the spheno-palatine, but 

 not involving that nerve or the branches pro- 

 ceeding from it ; and this, it is worth remark- 

 ing, is precisely the disposition of the ganglion 

 in the dog and some other animals. Different 

 views have been taken of the nature and rela- 

 tions of this ganglion: the Meckels, by the 

 elder of whom it was discovered, Bichat, Boyer, 

 and others, have regarded it as belonging pro- 

 perly to the fifth nerve, and formed by the 

 branches which have been mentioned : Cloquet, 

 on the other hand, considers and describes it 

 as a pail of the ganglionic or sympathetic 

 system, and all the nerves connected with it, 

 as well the original spheno-palatine branches 

 as the others, to be branches from it : Cruveil- 

 hier again, while he admits the existence of 

 ganglionic structure, yet leaves it uncertain 

 whether he regards it as a sympathetic or a 

 cerebro-spinal ganglion, but he differs from 

 Cloquet in maintaining that " the nerves," 

 which seem to arise from it, " are not detached 

 from the ganglion itself, and come directly 

 from the superior maxillary." The opinions of 

 Cloquet and Cruveilhier appear to the author 

 to be both, to a certain degree, well-founded. 

 The ganglion would seem not to be properly a 

 part of the fifth nerve, because, 1 . it is not, as 

 he believes, present in animals below the mam- 

 malia ; 2. it is not always present even in them, 

 and in neither case is the general distribution 



* Mem. de 1'Acad. de Berlin, 1794. 



of the part of the fifth nerve, with which it is 

 connected, influenced by its absence ; 3. it is 

 manifestly different in its characters from the 

 fifth nerve and from the branches of the nerve 

 to which it is attached, nor does it resemble 

 the cerebro-spinal ganglia, the peculiar appear- 

 ance of these bodies, viz. white filaments enter- 

 ing and emerging, their continuity being appa- 

 rently interrupted by an interposed mass of 

 cineritious matter, not being observable; while, 

 on the other hand, it resembles the ganglia of 

 the sympathetic, and is actually connected with 

 that nerve by a branch having precisely the 

 same qualities with those which proceed from 

 it, viz. by the inferior branch of the Vidian 

 nerve: for those reasons the author would 

 adopt the opinion of Cloquet, that the ganglion 

 is properly a part of the ganglionic system, and 

 that it is only accessory to the fifth nerve. On 

 the other hand, it appears to him that Cloquet 

 is mistaken in considering the ganglion as the 

 source of all the nervous filaments connected 

 with it, and more particularly of the spheno- 

 palatine branches of the second division of the 

 fifth, to which in man the ganglion is attached, 

 for, as has been already stated, the general dis- 

 tribution and existence of these branches are 

 not at all influenced by the absence of the gan- 

 glion, and when present it allows in general, as 

 Cruveilhier has observed, the nerves to be fol- 

 lowed up and down from the swelling, and 

 lastly, any obscurity existing with regard to 

 this point in the human subject will be at once 

 removed by reference to the disposition of the 

 ganglion in other animals, in none of which 

 that the author has examined does it involve 

 the nerve, but is merely connected to it either 

 by filaments or by one extremity, the continuity 

 of the nerve being altogether uninterrupted, 

 and a marked contrast being to be observed 

 between the characters of the two parts : thus 

 in the dog, the ganglion is an oblong dark- 

 grey swelling, with the posterior extremity of 

 which the Vidian nerve is united, while its an- 

 terior is attached to the naso-palatine nerve. 

 The author, therefore, concurs in the opinion of 

 Cruveilhier, so far as to regard the nerves con- 

 nected with the ganglion, for the greater part, 

 as branches of the fifth nerve and not of the 

 ganglion; but he would exclude from this view 

 the Vidian nerve, or at least its carotidean 

 branch, which appears to him to belong to the 

 sympathetic system. (See posterior branch of 

 ganglion.) 



The disposition of this ganglion throughout 

 the animal series is an object of interest. The 

 author cannot assert its existence in the mam- 

 malia universally, but from indirect considera- 

 tions it appears to him likely that it does exist, 

 generally at least, in animals of that class. Jt 

 is asserted in the work* of Desmoulins and 

 Majendie on the Anatomy of the Nervous Sys- 

 tem in vertebrate Animals, that " there does 

 not exist any trace of it in cats, dogs, the rumi- 

 nantia, the rodentia, the horse, &c. ;" and it is 

 reasonable to infer that they had found it in 

 others. Now their statement with regard to 



* Tom. ii. p. 396. 



