286 



FIFTH PAIR OF NERVES. 



its absence is, in the majority of the instances 

 which they have selected, positively incorrect, 

 for the author has ascertained its existence 

 most satisfactorily in the dog, the horse, the 

 cat, the cow, and the rabbit. Nor is any ex- 

 ception to its existence mentioned by Cuvier, 

 and hence he thinks it likely that it does exist 

 generally, if not universally, throughout the 

 class. It is not however similarly disposed in 

 all ; in some it is connected with the primitive 

 naso-palatine nerve; in others with its nasal; 

 and in others again with its palatine division : 

 in some it gives off few filaments ; in others, 

 the horse, e. g. they are numerous beyond de- 

 scription. The ganglion does not appear to 

 exist in the inferior classes. 



From the spheno-palatine ganglion or nerve, 

 according to the view of their source adopted, 

 there is given off a considerable number of 

 branches, which run in different directions and 

 have different destinations : they have been 

 distinguished into four sets, viz. superior, infe- 

 rior, internal, and posterior. The superior 

 branches are very delicate and, in some in- 

 stances at least, numerous. Among them are 

 described and represented by Arnold two long 

 slender filaments, which join the optic : ano- 

 ther is also mentioned by him to be sometimes 

 found connected with the ophthalmic ganglion. 

 The discovery of this connection between the 

 two ganglia is due to Tiedemann, who found, 

 upon the left side of a man, an anastomosis 

 between them, established by a filament, of 

 tolerable size, which, arising from the inner face 

 of the spheno-palatine, entered the orbit and 

 passing above the inferior branch of the motor- 

 oculi nerve, where it gives off the short root, 

 went in company with the last to gain the in- 

 ferior and posterior part of the ophthalmic gan- 

 glion ;* and beside those there may be found, 

 in favourable subjects, others, which seem 

 destined to the posterior ethmoidal cells. The 

 inferior branch is the largest given off by the 

 ganglion; it is distributed principally to the 

 palate, and hence is called " the palatine ;" 

 but it supplies the nostril also in part, and 

 hence it has been suggested by J. F. Meckel, 

 that it might be appropriately called the 

 " naso-palatine:" this appellation has, however, 

 been applied by Scarpa to one of the internal 

 branches, and it has been already explained 

 that it belongs more properly to the original 

 branch before its junction with the ganglion. 

 The palatine nerve descends from the ganglion 

 into the spheno-maxillary fossa, posterior to 

 the internal maxillary artery and toward the 

 ptery go- palatine canals, and after a short course 

 divides into three branches ; an anterior, larger 

 one, denominated " the great palatine," and 

 two posterior smaller branches, " the lesser 

 palatine nerves." 



These branches continue to descend in com- 

 pany until they reach the superior apertures of 

 the canals ; they then enter the canals and are 

 transmitted downward through them to the 

 palate and fauces. The great palatine descends 

 through the anterior pterygo-palatine canal, 



* Journal Cpmpl. vol. xxiv. Arnold. 



in company with a branch of the palatine 

 artery, at the same time inclining forward : 

 during its descent it gives off, in some in- 

 stances before, in others after it has entered 

 the canal, either one or two filaments, which 

 descend inward, pass through the nasal process 

 of the palate bone, and enter the nostril at the 

 back part of the middle meatus, between the 

 posterior extremities of the middle and in- 

 ferior turbinate bones : one of them is dis- 

 tributed to the membrane of the middle bone 

 and of the middle meatus ; the other to that 

 of the convex surface of the inferior bone : 

 when a single branch arises from the palatine 

 it divides into two, which follow a similar* 

 distribution; these branches are denominated 

 by the elder Meckel inferior nasal nerves in con- 

 tradistinction to the superior nasal, to be de- 

 scribed, given off by the ganglion and by the 

 Vidian nerve. Another filament is described 

 by Cloquet arising from the palatine shortly 

 before it escapes from the canal, entering the 

 nostril through the perpendicular plate of the 

 palate bone, running along the margin of the 

 inferior turbinate bone, and lost upon the 

 ascending process of the superior maxillary 

 bone, often also contained in an osseous canal. 



The great palatine nerve, then, for the most 

 part divides into three branches, of which one, 

 the smallest, descends through an accessory 

 canal, in the pterygoid process of the palate- 

 bone, leading from the anterior, and escapes 

 from it inferiorly into the soft palate in which 

 it is consumed. 



The other two escape from the pterygo- 

 palatine canal, through the posterior palatine 

 foramen, into the palate : at emerging from 

 the foramen they are situate very far back, 

 in the posterior angle of the hard palate on 

 either side, and behind the last molar tooth 

 of the upper jaw; they are immediately super- 

 ficial to the periosteum, and above the other 

 structures of the palate ; they are lodged, 

 along with the branches of the accompanying 

 artery, in channels upon the inferior surface 

 of the palatine processes of the palate and the 

 superior maxillary bones; they pass forward, 

 one along the alveolar arch, the other toward 

 the middle line of the palate, and subdivide, 

 each, into several branches, which are dis- 

 tributed to the structures of the hard palate, 

 the mucous glands and membrane, and to the 

 gums, and communicate in front with branches 

 of the naso-palatine ganglion. 



In some instances the palatine nerve does 

 not divide into those ultimate branches until 

 after it has escaped from the palatine canal ; 

 but their disposition in such cases is in other 

 respects the same. 



The lesser palatine nerves are posterior to 

 the greater; they are transmitted also through 

 the pterygo-palatine canals, the first through the 

 posterior, the second through the external. 



The first, the larger of the two, and called 

 middle palatine nerve, escapes from the canal 

 inferiorly in front of the hamular process of the 

 sphenoid bone, and divides into filaments', 

 which are distributed to the soft palate and its 

 muscles. 



