THE FACE 



389 



behind which is a shallow, wide, vertical groove, which is continued 

 on the superior border as an emargination. This groove receives the 

 upper canine tooth. Close to the anterior margin are two or more 

 small mental 1 foramina, the anterior orifices of the inferior dental 

 canal. Behind the canine swelling, midway between the upper and 

 the lower border, are two larger openings of the same canal. The 

 anterior opening is situated in the shallow groove mentioned above, 

 and the posterior three or four millimetres behind it. The anterior is 



FIG. 311. 



Canine. 



Incisors. 



Symphysis. 



Coronoid Process. 



TEMPORAL. 



Superior or Sigmoid Notch. 

 Condyle. 



Inferior Notch. 

 - Angle. 



Mental Foramina. 



DIGASTRIC. 



MASSETER. 



LOWER JAW, LEFT SIDE, OUTER SURFACE. 



usually larger than the posterior, and may be double ; the posterior 

 may be very small or entirely absent. There is frequently a second 

 smaller posterior foramen below, either behind or in front of the main 

 foramen, and there are several smaller inconstant openings on and 

 around the canine swelling. The buccinator muscle is attached to the 

 external surface along a line a little below the upper border, and the 

 digastric muscle is attached to the posterior lower part. 



The internal surface of the body of the mandible (Fig. 312) pre- 

 sents little worthy of note. It has the shape of the external surface ; 

 the upper and lower borders are nearly parallel, and the anterior end 

 is produced into an upward and forward prolongation to receive the 

 canine and incisor teeth. It is almost flat, slightly convex from above 

 downward, and curved from behind forward and inward. Near the 

 posterior end of its upper border is the beginning of the obscure 

 internal oblique line which runs downward and forward and marks 

 the attachment of the mylo-hyoid muscle. 



1 From mentum. the chin. 



