230 THE VISCERA. 



112). — The soft palate is the free curtain-Hke structure which 

 forms the caudal part of the roof of the mouth. It is attached 

 to the caudal border of the palatal plates and the ventral border 

 of the perpendicular plates, of the palatine, and to the pterygoid 

 processes and hamuli of the sphenoid, and extends some dis- 

 tance caudad of the hamuli. It thus forms a rather long and 

 narrow curtain separating the caudal part of the nasal cavity 

 from the mouth. Caudad it ends in a free arched border (Fig. 

 66, 4) which is at about the level of the epiglottis, and may lie 

 against the cranial or the caudal surface of the latter. The 

 narrowed passage bounded by the margin of the velum palat- 

 inum dorsad and the tongue ventrad is the isthmus faucium. 

 From the sides of the velum a short distance from the caudal 

 border a fold of mucosa passes ventrad to the side of the 

 tongue; a short distance caudad of this a similar fold passes to 

 the floor of the pharynx. These folds form the cranial and 

 caudal pillars of the fauces. Between these folds is a shallow 

 pocket, from the bottom of which there arises a prominent pro- 

 jection or swelling which is one of the two tonsils (Fig. 95, d). 

 Each tonsil is a reddish, lobulated gland, lymphoiil in the 

 adult, nearly a centimeter in length, and about one-third as 

 long as broad, with its long axis craniocaudad. 



The velum palatinum consists of two layers of mucous 

 membrane, oral and nasal, with intervening muscular and con- 

 nective tissue. Xhe muscles of the soft palate in the cat are 

 as follows: 



M. tensor veli palatini (Fig. 66, d, d\ page 112). 



Origin from the ventral surface of the body of the sphenoid 

 between the foramen ovale and the groove for the Eustachian 

 tube. The muscle ends in a flat tendon which passes over the 

 .hamular process (3) of the pterygoid bone. 



Insertion by spreading . out in the soft palate into an 

 aponeurosis which joins the aponeurosis of the opposite muscle 

 and lies between the mucous membrane of the mouth and that 

 of the nose. 



Action. — Stretches the palate. 



M. levator veli palatini (Fig. 66, e, e'). — A flat triangular 

 muscle which lies within the tensor. 



