318 THE MOUTH. 



also send some small twigs. The veins, after forming the 

 pharyngeal plexus y return into the jugular and superior 

 thyroid. 



Nerves. The nerves of the pharynx are the c/losso- 

 pharyngealj (Fig. 91,) the pharyngeal "branch of the par 

 vagum, all belonging to the eighth pair, and branches 

 from the superior cervical ganglion of the sympathetic. 



SECTION IX. 

 THE MOUTH. 



The mouth, (Fig. 93,) situated at the commencement of 

 the digestive tube, is composed of the organs of prehension, 

 FlG 93 mastication, insaliva- 



tion, and part of those 

 of deglutition. Hence it 

 is evident that it con- 

 sists of an apparatus 

 both complicated and 

 various. Having con- 

 sidered all the organs 

 forming the mouth, 

 successively and in de- 

 tail, it now seems 

 proper to look at them 

 for a moment collect- 

 ively in their several relations to the mouth as a whole, 

 and in their united and harmonious action in the dis- 

 charge of the various functions they are called upon to 

 perform. 



The cavity of the mouth is bounded superiorly by the 

 palatine processes of the superior maxillary and palate 

 bones, which constitute its roof; infer iorly by the mylo- 



FIG. 93 represents a view of the cavity of the mouth, a Superior lip turned 

 up. 6 Froenum of the upper lip. c Inferior lip turned down, d Frsenum of 

 the lower lip. e e Internal surface of the cheeks. // Point where the duct 

 of steno enters the mouth, g Roof of the mouth, h Anterior portion of the 

 lateral half arches, i Posterior portion of the lateral half arches, j Velum 

 pendulum palati. k Tonsils. I Tongue. 



