288 



FIFTH PAIR OF NERVES. 



it escapes from its posterior aperture into the 

 foramen lacerum anterius basis cranii : in this 

 it is contained in the fibrous structure by 

 which the foramen is closed, and is situate 

 at the outer side of and beneath the internal 

 carotid artery, as that vessel ascends, from 

 the aperture of its canal in the petrous bone, 

 into the cavernous sinus. Here also, or even 

 before it has escaped from the Vidian canal, 

 it receives, when single, a filament of com- 

 munication from the superior cervical ganglion 

 of the sympathetic: this filament had been 

 long regarded as arising from the posterior 

 branch itself, and though at present gene- 

 rally* considered a branch from the sympa- 

 thetic it has been for the most part described, 

 in systematic works, as such under the name 

 of the inferior, deep, sympathic, or carotidean 

 branch of the Vidian nerve. In its direction 

 it certainly resembles a branch of that nerve ; 

 but in that particular it is equally entitled to 

 be regarded one from the sympathetic to the 

 spheno-palatine ganglion, it being either from 

 before backward and from above downward, 

 or from behind forward and from below up- 

 ward. Further, in sensible qualities it strictly 

 resembles other branches of the latter nerve ; 

 it is, as has been stated, at times separate from 

 the proper Vidian, and connected directly with 

 the spheno-palatine ganglion ; and it is, in fact, 

 but one of the branches which ascend into the 

 cranium from the superior cervical ganglion 

 along the internal carotid artery, so that it 

 would be equally correct to describe that fila- 

 ment which is connected with the sixth nerve 

 as a branch of that nerve, as to style the fila- 

 ment in question a branch of the Vidian nerve. 



The view of the nature of this filament here 

 advanced is, however, not universally admitted. 

 Cruveilhier objects to it because the cranial 

 branch of the Vidian nerve appears to him to 

 resemble in all respects the carotidean : this, 

 however, cannot be considered a valid objec- 

 tion, it can only prove that one branch may be 

 as much allied to the ganglionic system as the 

 other, but the validity of the assertion may be 

 questioned; however it may be in man, the 

 characters of the two branches in the larger 

 quadrupeds, the horse e. g. are sufficiently 

 distinct, the cranial branch being of a pure 

 white colour, and the carotidean having a gan- 

 glionic enlargement upon it at its junction with 

 the cranial. 



While traversing the pterygoid canal, soon 

 after it has entered that canal, and in some cases 

 even before, the posterior branch of the gan- 

 glion gives off from its inner side two or three 

 filaments, denominated by the elder Meckel 

 posterior superior nasal : these enter the poste- 

 rior superior part of the nostril, in one case by 

 passing through the spheno-palatine foramen, 

 in the other by perforating the inner wall of 

 the pterygoid canal, and are distributed to the 

 posterior part of the lateral wall of the nostril, 

 to the root of the septum, to the sphenoidal 

 sinus and to the lateral wall of the pharynx 

 in the vicinity of the orifice of the Eustachian 



* Bock, Cloquet, Hirzel, J. F. Meckel. 



tube. These branches frequently arise from 

 the ganglion itself by a single filament, de- 

 nominated by Bock the pharyngeal nerve, and 

 represented by Arnold among the internal 

 branches of the ganglion : it divides into fila- 

 ments distributed to the several parts men- 

 tioned. 



After the junction of the sympathetic fila- 

 ment, the posterior branch is continued through 

 the fibrous structure already mentioned, ex- 

 ternal to the internal carotid artery, and 

 thus enters the cranium. It then passes out- 

 ward, backward, and upward, upon the ante- 

 rior surface of the petrous bone, beneath 

 the third division of the fifth, very near 

 its attachment to the Gasserian ganglion, 

 and enclosed in the dura mater : it is at the 

 same time lodged in a channel upon the sur- 

 face of the bone. It is stated by Cloquet that 

 it here sends into the cavity of the tympanum 

 by two canals, the orifices of which are to be 

 seen in the channel one above the other, two 

 filaments of extreme delicacy, which go to 

 anastomose together upon the promontory, and 

 to communicate with a filament of the supe- 

 rior cervical ganglion, and with the glosso- 

 pharyngeal nerve. According to Hirzel,* this 

 connection between the superficial branch of 

 the Vidian and the tympanic branch of the 

 glosso-pharyngeal nerve on the nerve of Jacob- 

 son, takes place in the vicinity of the junction 

 of the former with the facial nerve. Accord- 

 ing to Arnold,f the superficial branch of the 

 Vidian nerve is, as proved by the researches of 

 others and his own, not simple, but composed 

 of two or of several filaments, and is accom- 

 panied by one or more very delicate filaments 

 from the carotid plexus. In one instance he 

 found the petrous nerve composed of four 

 filaments on the right, and three on the left. 

 The existence of several distinct filaments in 

 the Vidian nerve may be easily observed in the 

 larger animals. It pursues the course men- 

 tioned, until it has reached the hiatus Fallopii, 

 through which it is transmitted to the aqueduct 

 of Fallopius, where it meets and becomes in- 

 timately connected with the facial portio dura 

 nerve. At their junction the facial nerve pre- 

 sents a gangliform swelling, from which two 

 very delicate filaments proceed to the auditory 

 nerve. % 



From the time that the posterior branch of 

 the ganglion enters the cranium until it has 

 joined the facial nerve, it is called the cranial 

 or superficial petrous branch of the Vidian 

 nerve ; by Arnold petrosus superficial major 

 in contradistinction to another nervous filament, 

 which connects his t otic' ganglion to the tym- 

 panic branch of the glosso-pharyngeal nerve ; 

 but the application of either of these epithets 

 would be rendered unnecessary by ceasing to 

 consider the filament by which the posterior 

 branch of the ganglion is connected to the 

 sympathetic, a branch of the former. 



The posterior branch is also known by other 



* Journ. Compl. t. xxii. 

 t Journ. Compl. t. xxiv. 



$ Arnold. See lingual branch of third divisioa 

 and chorda tympani. 



