216 



DIGESTION. 



brse. It is imperfectly separated from the cavity of the mouth by the velum pendulum 

 palati, a movable musculo-membranous fold continuous with the roof the mouth and 

 marked by a line in the centre, which indicates its original development by two lateral 

 halves. This, which is called the soft palate, when relaxed, presents a concave surface 

 looking toward the mouth, a free, arched border, and a conical process hanging from the 

 centre, called the uvula. On either side of the soft palate, are two curved pillars or arches. 



The anterior pillars of the fauces are formed by the palato-glossus muscle on either 

 side and run obliquely downward and forward, the mucous membrane which covers 

 them becoming continuous with the membrane over the base of the tongue. The posterior 

 pillars are more closely approximated to each other than the anterior. They run obliquely 

 downward and backward, their mucous membrane becoming continuous with the mem- 

 brane covering the sides of the pharynx. Between the lower portion of the anterior and 

 posterior pillars, are the tonsils; and in the substance of, and beneath the mucous mem- 

 brane of the palate and pharynx, are small glands, which have already been described. 



In Fig. 52 are shown the cavities of the mouth and pharynx with their relations to 

 the nares and the larynx. 



FIG. 53. Muscles of fJie pharynx, etc. (Sappey.) 



1, 2, 3, 4, 4, superior constrictor; 5, 6, 7, 8, middle constrictor; 9, 10, 11, 12, inferior constrictor; 18, 18. stylo- 

 pharynseus; 14, stylo-hyoid muscle; 15, stylo-glossus ; 16, hyo-glossus ; 17, mylo-hyoid muscle; 18, buccinator 

 muscle ; 19, tensor palati; 20, levator palati. 



The isthmus of the fauces, or the strait through which the food passes from the mouth 

 to the pharynx, is bounded above, by the soft palate and the uvula ; laterally, by the pil- 

 lars of the palate and the tonsils ; and below, by the base of the tongue. 



