PALATO-GLOSSUS PALATO-PHARYNGEUS. 169 



muscle ; by its internal surface with the levator palati, internal 

 pterygoid plate and superior constrictor. In the soft palate, its ten- 

 dinous expansion is placed in front of the other muscles and in con- 

 tact with the mucous membrane. 



The azygos uvula is not a single muscle, as might be inferred 

 from its name, but a pair of small muscles placed side by side in 

 the middle line of the soft palate. They arise from the spine of 

 the palate bone, and are inserted into the uvula. By their anterior 

 surface they are in contact with the tendinous expansion of the 

 levatores palati, and by the posterior with the mucous membrane. 



The two next muscles are brought into view throughout the whole 

 of their extent, by raising the mucous membrane from off the pillars 

 of the soft palate at each side. 



The palato-glossus (constrictor isthmii faucium) is a small fasci- 

 culus of fibres that arises in the soft palate, and descends to be 

 inserted into the side of the tongue. It is the projection of this 

 small muscle covered by mucous membrane, that forms the anterior 

 pillar of the soft palate. It has been named constrictor isthmii fau- 

 cium from a function it performs in common with the palato- 

 pharyngeus, viz. of constricting the opening of the fauces. 



The palato-pharyngeus forms the posterior pillar of the fauces ; 

 it arises by an expanded fasciculus from the lower part of the soft 

 palate where its fibres are continuous with those of the muscle of 

 the opposite side ; and is inserted into the posterior border of the 

 thyroid cartilage. This muscle is broad above where it forms the 

 whole thickness of the lower half of the soft palate, narrow in the 

 posterior pillar, and again broad and thin in the pharynx where it 

 spreads out previously to its insertion. 



Relations. In the soft palate it is in relation with the mucous 

 membrane both by its anterior and posterior surface ; above, with the 

 muscular layer formed by the levator palati, and below with the mu- 

 cous glands situated along the margin of the arch of the palate. In 

 the posterior pillar of the palate, it is surrounded for two-thirds of 

 its extent by mucous membrane. In the pharynx, it is in relation 

 by its outer surface with the superior and middle constrictor muscles, 

 and by its inner surface with the mucous membrane of the pharynx, 

 the pharyngeal fascia being interposed. 



Actions. The azygos uvulse shortens the uvula. The levator 

 palati raises the soft palate, while the tensor spreads it out laterally 

 so as to form a septum between the pharynx and posterior nares 

 during deglutition. Taking its fixed point from below, the tensor 

 palati will dilate the Eustachian tube. The palato-glossus and 

 pharyngeus constrict the opening of the fauces, and by drawing 

 down the soft palate they serve to press the mass of food from the 

 dorsum of the tongue into the pharynx. 



22 



