1868.] 



Buccal Branch of the Fifth Cranial Nerve. 



457 



of the jaw and the anterior border of the masseter to the fat of the cheek, 

 where they anastomosed with branches of the portio dura, and doubt- 

 less ended in the integument. These nerves represented, I beUeve, the 

 branches which the long buccal nerve usually gives off before it enters the 

 buccinator muscle, and were the only parts of that nerve which arose on 

 this side of the head from the second division of the fifth. The remaining 

 part of the long buccal nerve arose from the inferior maxillary trunk and 

 entered the buccinator in the usual locality. When followed into the sub- 

 stance of the muscle, it passed obliquely and gave off branches of great 

 delicacy, many of which were traced into the mucous membrane of the 

 cheek. Followed upwards to its origin, the long buccal nerve was seen to 

 divide at the foramen ovale into two parts, of which one was traced with- 

 out difficulty directly into the Gasserian ganglion, and must therefore be re- 

 garded as sensory ; the other, connected with the fasciculus, from which the 

 temporal and masseteric nerves arose, was followed upwards to the motor 

 root of the fifth. Almost immediately after receiving this offshoot from 

 the motor root, the buccal nerve gave origin to the nerve of supply for the 

 external pterygoid muscle, and the fibres of the motor root were to all ap- 

 pearance prolonged directly into this pterygoid branch, whilst the fibres 

 from the sensory ganghon could be distinctly traced into the proper buccal 

 part of the nerve. 



There can be no doubt that in this case the entire buccal nerve on the left 

 side was purely sensory. There can also be no doubt that those branches 

 arising from the superior maxillary trunk on the right side, which passed 

 to the surface over the buccinator, were purely sensory. The remaining 

 part of the right nerve also, though connected with the motor root of the 

 fifth, yet parted to all appearance with its motor fibres before it proceeded 

 to its destination. 



I may take this opportunity of referring to a case of variation in the 

 origin of the buccal nerve, which, so far as I know, has not yet been re- 

 ferred to by British anatomists, and which gives additional evidence of the 

 sensory nature of the nerve. In the Bulletins de la Soc. Anat. de Paris, 

 1853, S. 109 (quoted in Krause und Telgmann * Die Nerven-Varietaten,' 

 Leipzig, 1868), M. Gaillet describes the nerve as arising directly from the 

 Gasserian ganglion, without having any connexion with the motor root, 

 then passing out of the cranium through a special foramen midway between 

 the F. rotundum and F. ovale, and lying between the great wing of the 

 sphenoid and external pterygoid muscle on its course to its distribution. 



Variations in the usually described arrangements of the structures in the 

 human body have, as a rule, been studied either from their bearings on 

 questions connected with practical medicine and surgery, or from the light 

 which they throw on the development and morphology of parts and organs, 

 out, as these cases prove, their study is not without interest from the teleo- 

 logical point of view. 



