224 THE FIFTH PAIR' OF NERVES. 



others go to this muscle from the seventh pair. In 

 the buccinator these fibrils are usually lost; but some- 

 times a few of them may be traced to the lower lip. 



" The third branch, in the order of its being given 

 off, is the dental nerve. This is generally considered 

 the continuation of the trunk of the inferior maxillary 

 nerve. It passes across the pterygoideus and enters a 

 canal (the dental canal), on the inner face of the lower 

 jawbone, near the upper edge, and at the bending or 

 angle of the jaw. It takes its course along the interior 

 of the bone (the canal), close to the roots of the teeth, 

 and sends out filaments to each of them. Emerging 

 through the lower maxillary foramen, it divides into 

 two branches, one of which is distributed in numerous 

 ramifications on the outside of the lower lip, and the 

 other in fewer ramifications on the inside. These are 

 evidently sensitive fibrils, the power of motion being 

 derived from the seventh pair of nerves. 



" The fourth branch in point of order, but which 

 does not enter the ' dental canal/ is the gustatory or 

 lingual nerve, the largest of the four. It is singularly 

 fiat, like a little ribbon. It runs along the inside of 

 the lower jaw, and a branch of it enters a foramen in 

 the jaw to supply the roots of the incisor teeth ; but 

 the main nerve, proceeding obliquely downward, gives 

 fibrils to the submaxilhiry glands, and to the glands 

 and muscles at the base of the mouth generally. These 

 fibrils form true plexuses about the salivary glands and 

 the muscles of the tongue. They anastomose freely 

 with the twelfth pair (the lingnales or motor nerve of 

 the tongue), as the twelfth had already done with the 

 seventh (the 'portio dura'). The gustatory branch 

 penetrates the substance of the tongue between the 

 stylo and genio-glossal muscles, passing obliquely to 



