268 COMPARATIVE ANATOMY OF THE TEETH. 



front of the meatus externus, supplying the articulation of 

 the jaw, the meatus auditorius, the cartilages of the ear, and 

 then mounting over the zygoma, divides into anterior and 

 posterior branches ; which follow the course of the temporal 

 artery. This nerve connects with the facial. The superior 

 division of the inferior maxillary nerve has the motor 

 trunk and divides into the masseter, the deep temporal, the 

 buccal, and ihepterygoid branches. 



The masseter nerve passes in front of the neck of the 

 lower jaw and the insertion of the temporal muscle, through 

 the sigmoid notch, and is distributed to the masseter mus- 

 cle. The deep temporal nerves ascend to the temporal mus- 

 cle, in which they are lost. They are two in number, an 

 anterior and a posterior. 



The buccal nerve goes between the pterygoid muscles, 

 giving some filaments to these, and is then distributed 

 upon the buccinator, forming a plexus upon this muscle 

 with the infra-orbital and the facial. The pterygoid nerve 

 consists of two or three branches, which go to the ptery- 

 goid muscles. 



SECTION V. 



COMPARATIVE ANATOMY OF THE TEETH. 



The examination of similar organs in the inferior ani- 

 mals, has always been a subject of deep interest and close 

 study to the anatomist and physiologist, and always re- 

 garded by them as essential to the full understanding of 

 the structure and functions of the various organs of the 

 human body to the full development of medical science. 



What is true of the body, as a whole, applies with equal 

 force to its several parts. Each organ finds its analogue 

 in some one or more of the inferior animals; and the teeth, 

 as forming parts, and indispensable parts, of the human 

 frame, come in equally for their share of examination, in 

 this comparison of organs, among the inferior animals. 



The importance of this subject has now fully aroused 

 the master spirits of the profession to investigation in this 



