DEVELOPMENT OF THE FACE. 



15 



the ascending ramus again becomes oblique, to allow the lower 

 jaw to come in contact with the upper during mastication. The 

 mental eminence is produced after birth, and is a human charac- 

 teristic. It gives attachment to the depressores labii inferioris. 



The ascending ramus is peculiar to mammals. In other verte- 

 brates Meckel's cartilage forms the skeletal basis of the lower jaw 

 and articulates with the quadrate bone (incus) by its upper 

 articular extremity, the os articulare (malleus) (Fig. 10 0), The 

 part of Meckel's cartilage between the malleus and body of the 

 lower jaw forms the internal lateral ligament, and possibly also 

 the interarticnlar cartilage of the temporo-maxillary articulation. 



inter-artw 

 cart. 



condyle— 



ext. aud. 

 meat. 



post-glenoid sp. 



post-glenoid sp. 



ext. aud. 

 meat 



-mastoid 



cartiC^™' 10 

 condyle 



condyle 



rext. aud meat 

 paramastoid 

 ^post-glenoid sp. 

 cartilage 



Flo. 13. — The chief types of the Temporo-Maxillary Articulation. 

 A. Carnivorous Type. B. Omnivorous Type. C. Herbivorous Type. 



Gadow regards the angle of the jaw as the representative of 

 the os articulare. 



The Temporo-maxillary Articulation. — Two types of this joint 



