TEMPOBO-M A XILL ART ARTICULATION. 145 



portion called the ramus. In the adult, this forms nearly a 

 right angle with the body, making what is called the angle 

 of the jaw. Superiorly, the ramus terminates in two pro- 

 cesses, separated by a deep groove called the sigmoid notch. 

 The posterior process is the condyle, or condyloid process ; 

 the anatomy of which will be considered further on in treat- 

 ing of the temporo-maxillary articulation. The anterior pro- 

 cess, called the coronoid process, is for the attachment of the 

 temporal muscle, one of the most powerful of the muscles of 

 mastication. The greater portion of the external surface of 

 the ramus, extending down to the angle, is for the attach- 

 ment of the masseter muscle. The internal surface of the 

 ramus gives attachment to several muscles, viz. : the external 

 pterygoid, attached to the neck just below the condyle ; the 

 temporal, the attachment to the coronoid process being much 

 more extensive on the internal than on the external surface ; 

 and the internal pterygoid, which has its attachment at the 

 angle. 



Temporo -Maxillary Articulation. The various classes 

 of mammalia present great differences in the temporo-maxil- 

 lary articulation differences which indicate, to a great ex- 

 tent, their natural diet. In the carnivora, the long diameter 

 of the condyle is transverse, and it is so firmly embedded, in 

 the deep glenoid cavity of the temporal bone, as to admit of 

 extended movements in but one direction. In these animals, 

 lateral and antero-posterior sliding movements of the jaw are 

 impossible, and there is very little mastication of the food. 

 In the rodentia, the long diameter of the condyle is antero- 

 posterior, the peculiar gnawing movements in these animals 

 requiring a considerable sliding movement of the lower jaw 

 in this direction. In the herbivora, particularly the rumi- 

 nants, the condyle is small and slightly concave instead of 

 convex, as in most other animals. It moves on a large pro- 

 jecting surface on the temporal bone, and the entire jaw is 

 capable of remarkably extensive lateral movements. 

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