292 



FIFTH PAIR OF NERVES. 



toward its insertion, and are distributed to it at 

 that point, others ascend in the temporal fossa, 

 between the muscle and the bone, penetrate the 

 muscle, and are distributed, along with the 

 branches of the anterior deep temporal, with 

 which they anastomose freely, to the muscle at 

 its inferior anterior part. In the next place, 

 while between the masseter and the buccinator, 

 the nerve gives off backward several branches, 

 three or four, which are distributed to the buc- 

 cinator at its origin, to the buccal glands, and 

 to the membrane of the mouth ; as it lies upon 

 the last-named muscle, between the ramus of 

 the jaw and the angle of the mouth, it gives 

 filaments to it at its middle and anterior part, 

 which, like the former, both supply the muscle, 

 pass through its fibres, and are distributed also 

 to the buccal glands and membrane. Finally, 

 as the nerve approaches the angle of the mouth, 

 it divides into two, occasionally three, branches; 

 these two branches pursue the direction of the 

 nerve toward the angle, passing beneath the 

 facial vein and inclining, one upward, the other 

 downward; after a short course they are united 

 both to branches of the portio dura, the inferior 

 to a branch of the inferior or cervico-facial divi- 

 sion, the superior to one of the superior or tem- 

 poro-facial division of that nerve. By their 

 union they form conjoined branches or loops, 

 from each of which are given off several fila- 

 ments to the muscles of the mouth at their in- 

 sertion into the angle ; from the superior, more 

 particularly, to the buccinator, the zygomatic, 

 and levator anguli; and from the inferior to the 

 buccinator and depressor anguli oris. 



4. The fifth and last of these branches is the 

 plerygoid ; it is the smallest of them, and 

 arises from the anterior internal part of the 

 trunk ; it passes inward and downward, be- 

 hind the external pterygoid, and then between 

 the internal pterygoid and circumflexus palati 

 muscles ; it gives a filament of some size to 

 the latter muscle, and then entering into the 

 internal pterygoid at its upper extremity, it is 

 consumed altogether in that muscle. 



The external pterygoid also, at times, but 

 not uniformly, receives a distinct filament from 

 the trunk; when present it arises from the 

 front of the nerve, beneath the buccal branch, 

 and passes forward directly to the muscle, in 

 which it is consumed. The constitution of 

 these branches is peculiar, and is a matter 

 of much interest: involving physiological ques- 

 tions, this subject is deferred to another oc- 

 casion. 



In consequence of its connection with the 

 third division of the fifth, and more particularly 

 with the lesser packet of the nerve, this seems 

 a fit place to advert to the ganglion discovered 

 by Arnold, and by him denominated Otic 

 or auricular, of which the following sketch 

 has been taken from his own account. It 

 is situate at the inner side of the third branch 

 of the fifth, some lines beneath the foramen 

 ovale, at the part where the deep temporal, 

 the masseteric, and the buccal nerves are de- 

 tached from the same side, and a little above 

 the origin of the superficial temporal nerve: 



its posterior part touches the middle meningeal 

 artery, and the internal the internal pterygoid 

 muscle : an abundant adipose tissue surrounds 

 it : its form is not altogether regular, however 

 it approaches to an oval, flattened internally 

 and externally. It is united to the trunk 

 of the third division not merely by cellular 

 tissue, but by many filaments, which enter 

 into the formation of the ganglion ; these 

 filaments, which come solely from the lesser 

 portion of the nerve, are mostly extremely 

 short, and can only be observed when we 

 try to separate the ganglion from the trunk; 

 but in cases where the ganglion is situate 

 rather distant from the nerve, the filaments 

 are of course longer and can be more easily 

 observed. With regard to the branches of 

 the third division, the pterygoid nerve espe- 

 cially is in very intimate connection with the 

 otic ganglion, so that in a superficial examina- 

 tion it appears as if it arose from it; but, 

 in a more accurate investigation, it is clear 

 that this nerve soon after its origin penetrates 

 through a part of the substance of the ganglion 

 and takes up some of it : the slender branch, 

 which ramifies in the tensor palati, is likewise 

 in very intimate relation with this ganglion, 

 and distinguishes itself from the other branches 

 by its reddish appearance. The ganglion thus 

 communicates with the lesser packet of the 

 fifth : it also communicates with the glosso- 

 pharyngeal and with the facial* and auditory 

 nerves by means of the nervus tympanicus. 

 But, the ganglion being a body which is to 

 be regarded as distinct from the fifth nerve, 

 and not part of it, a further pursuit of its 

 connections and properties would be here out 

 of place. See SYMPATHETIC NERVE. 



The third division of the fifth descends from 

 the foramen ovale, outward into the zygomatic 

 fossa, posterior to the external pterygoid muscle, 

 before the superior part of the levator palati, 

 and internal and parallel to the middle me- 

 ningeal artery. After a course of half an inch 

 from the foramen, it divides for the most part 

 into two large branches, an anterior internal 

 one destined to the tongue, denominated the 

 lingual branch, and an external posterior one, 

 which is transmitted through the inferior max- 

 illary canal, and, escaping from this, through 

 the mental foramen, is distributed finally to 

 the muscles and integuments of the chin; this 

 second branch is called inferior dental, or 

 inferior maxillary nerve ; the latter, as has 

 been already intimated, appears much the 

 more appropriate appellation. 



The first branch bears, very generally, the 

 name of gustatory nerve from its presumed 

 connection with the sense of taste; but, since 

 the opinion that it is the nerve in which the 

 sense of taste resides has been brought into 

 question, and since, as will appear by-and- 

 bye, it is at least certainly not the sole nerve 

 of that sense, it is obvious that that name 

 should be discontinued. 



The manner in which the third division 

 finally divides is not always such as has been 

 described : in some instances it separates fairly 



