392 MAMMALIAN ANATOMY 



(1) The upper part is also the posterior border of the coronoid process. 

 It is twice as long as the lower part, narrow and rounded and deeply 

 emarginate, forming between the tip of the coronoid process and the 

 condyle the superior, or sigmoid, 1 notch. It becomes transversely 

 wider below and terminates near the inner end of the condyle. (2) 

 The lower part presents a sharp border beginning above at the outer 

 end of the condyle and running obliquely downward and inward to 

 meet, at the angle, the upturned posterior end of the lower border. 

 From this border the triangular space included between the angle 

 and the base of the condyle slopes forward and inward to become 

 continuous with the internal surface. This space receives the inser- 

 tion of the maxillo-auricular muscle. 



The angle is a blunt hook pointing inward and backward ; in the 

 natural state it is embedded in the masseter muscle. 



The condyle is a bony cylinder, four or five times as long as wide, 

 placed across the posterior border of the ascending ramus. The long 

 axis is not transverse to the long axis of the lower jaw, but forms with 

 it a decided angle ; the outer end is directed backward and the inner 

 end forward. When the two sides of the jaw are in place, however, 

 the two condyles lie in a line transverse to the long axis of the skull. 

 The condyle is narrow and pointed at the outer end. Its upper artic- 

 ular surface is emarginate in front, and separated behind from the 

 non-articular part by a straight line. The condyle is sometimes de- 

 scribed as the posterior part of the condyloid process, which is narrow 

 above, wide below, and not well defined on the outside ; it is separated 

 from the ramus by a neck. 



The external surface of the ascending ramus (Fig. 311) is almost 

 entirely occupied by a large deep fossa which is limited by an elevated 

 sharp superior border, a rounded lower border, and a well-defined line 

 from the outer tip of the condyle to the lower border. The fossa ends 

 in front in a shallow point near the posterior part of the outer surface 

 of the body of the bone. The temporal muscle is attached in the 

 fossa and to its edge ; the masseter is attached to the lower border. 



The internal surface (Fig. 312) has the shape of the external ; it 

 is flat, and slightly roughened for muscular attachment. The dental 

 foramen pierces the middle of the lower third obliquely forward and 

 outward and leads into the inferior dental canal, which lodges the 



1 From (Gr.) sigma, the letter 2 or S, in its older form C, and eides, like. 



