464 NERVOUS SYSTEM. 



superficial temporal artery, and thereby supply the middle part 

 of the integuments on the side of the head. It anastomoses 

 with the filaments of the frontal nerve, and with those of the 

 occipital. 



b. The Inferior Dental Nerve is placed between the other 

 two branches, and exceeds them in size. It descends between 

 the two pterygoid muscles, towards the posterior mental fora- 

 men. Just above the latter it detaches a small branch, the 

 mylo-hyoid, which occupies the small gutter on the bone lead- 

 ing downward from the posterior mental foramen. This branch 

 sends a filament to the submaxillary gland, then passes between 

 the anterior belly of the digastric muscle and the mylo-hyoi- 

 deus, to both of which it gives filaments, and finally winding 

 over the base of the lower jaw in front, it is lost upon the mus- 

 cles of the chin. 



The inferior dental nerve then enters the posterior mental 

 foramen, and divides into two branches, which run parallel 

 with one another through the 'canal in the middle of the spongy 

 structure of the bone, and send a great number of anastomotic 

 filaments to each other. One of the branches, the dental, pro- 

 perly speaking, as it passes along the ends of the roots of the 

 teeth, detaches a filament to each root, from the last grinder to 

 the first incisor tooth inclusively: it also sends a filament to the 

 gum intermediate to every two teeth. Ail of these filaments 

 arise from the dental nerve, at places behind the points of des- 

 tination; so that they have before reaching the latter, to run 

 forwards and upwards through little canals in the cellular 

 structure of the bone. 



The other branch of the inferior dental nerve is the mental; 

 it does not advance so far forward in the bone as the pre- 

 ceding, but issues from it at the anterior mental foramen, and 

 immediately is divided into two fasciculi, the inferior labial 

 nerves. The internal fasciculus is distributed by filaments upon 

 the muscles of the chin and lower lip, the contiguous lining 

 membrane of the mouth and the labial glands. The external 

 fasciculus rises upwards and is distributed on the muscular 

 structure, about the under part of the commissure of the lip, and 

 to the contiguous lining membrane and glands of the mouth. 



c. The Lingual Nerve descends in company with the infe- 

 rior dental, but in advance of it, and diverging slightly. While 



