THE INFERIOR MAXILLARY. 55 



External is the canine eminence, which marks the 

 position of the root of the canine tooth ; it is less devel- 

 oped than the canine eminence of the upper jaw. 

 About an inch and a quarter external to the median line 

 is the mental foramen, at which a leash of filaments of 

 the inferior dental nerve make their appearance upon 

 the face. The mental is an oval foramen, two lines 

 in its transverse and three lines in the conjugate di- 

 ameter, with its long diameter parallel with the lower 

 border ; it is almost directly in a line below the second 

 bicuspid tooth. It is a little below the middle line of 

 the bone ; an examination of a number of inferior 

 maxillary bones shows it to be at the junction of the 

 inferior two-fifths with the superior three-fifths of the 

 bone. Posterior to the mental foramen, the outer sur- 

 face is convex from above downward. An oblique 

 ridge the external oblique line begins posterior to 

 the mental foramen and curves backward and upward, 

 becoming continuous with the anterior edge or border 

 of the ramus. The internal surface is strongly concave 

 from side to side, convex from above downward. It 

 presents on each side of the median line, below the 

 middle of the bone, two tubercles the genial tuber- 

 cles for muscular attachment. These tubercles are 

 arranged in pairs, two above and two below. A little 

 posterior to the superior genial tubercles, and running 

 backward and slightly upward, is the internal oblique 

 line, or mylo-hyoid ridge, which gives attachment to the 

 mylo-hyoid muscle. This ridge is not well defined ante- 

 riorly, but becomes prominent beneath the molar teeth. 

 It passes upward and backward on the inner surface of 

 the ramus. Above the mylo-hyoid ridge, on each side 

 of the median line, is a shallow depression, which lodges 

 the sublingual gland. At the sides of the inferior genial 



