THE FACE 391 



than half-way through the bone. The anterior part of the alveolar 

 border turns inward and becomes nearly transverse to the axis of the 

 bone ; it is connected with the posterior part by a sharp curved ridge 

 lying on the inner side of the bone. It is almost entirely occupied by 

 the large opening of the alveolus for the canine teeth, between which 

 and the symphysis the border is narrow and contains, in a perfect jaw, 

 three transversely placed small alveoli for the incisors. The canine 

 opening is oval ; the long diameter is directed from before backward ; 

 its edge is sharp, and its cavity is curved backward and downward. 

 The alveoli are subject to variation. Those for the incisors are rarely 

 entirely separated from one another or placed in a transverse line. 

 Age and disease lead to the loss of the teeth and the subsequent ab- 

 sorption of the alveoli. 



The lower border of the body is known as its base. It is heavy 

 and rounded except just in front near the symphysis, where it is sharp 

 and lies on the median side of the bone. Near its middle, where the 

 digastric muscle is attached, it frequently bends slightly upward. 



The Ascending Ramus has the shape of a right-angled triangle, 

 whereof the lower anterior angle is truncated and applied to the pos- 

 terior end of the body. Its upper part is the coronoid 1 process. The 

 condyle for articulation with the temporal bone of the cranium is 

 placed transversely across its posterior border. The ascending ramus 

 presents three borders and two surfaces : 



The anterior-superior border begins above at the tip of the coro- 

 noid process. It passes, as a thin edge, at first upward and forward, 

 then arches downward and forward, becomes gradually broader, and 

 ends below in the upper border and external surface of the body. It 

 faces at first upward and backward, then upward and inward, and 

 finally upward and outward. It is more sharply defined from the 

 external than from the internal surface. 



The inferior border is continuous with the inferior border of the 

 body, which it resembles. The posterior part is narrow and turns 

 inward to end in the angle of the jaw. The border affords attach- 

 ment to the masseter muscle. 



The posterior border is divided into two parts by the coudyle. 



1 From (Gr.) corone, a book like a crow's bill, and eid.es, like. Corone was also 

 applied to the hook on the tip of the bow to which the bow-string was attached ; 

 in this sense it was first introduced into anatomy by Galen. 



