664 DISSECTION OF THE PHABYNX. 



the tongue ; from this spot the fibres ascend in front of the tonsil to 



the anterior aspect of the soft palate, where they form a thin muscular 



stratum, and join those of the fellow muscle along the middle line. 



relations At its origin the muscle is blended with the glossal muscles, and 



at its insertion it is placed beneath the tensor palati. 



use- Action. The palato-glossus closes the isthmus of the fauces, 



bringing the soft palate into contact with the tongue, and approxi- 

 mating the anterior pillars, thus shutting off the mouth, from the 

 pharynx. 



Palato- The PALATO-PHARYNGEUS (fig. 233, Q ; 234, 4 ) is much larger than 



pharyngens ^ ne preceding muscle, and gives rise to the eminence of the pos- 



formstwo terior pillar of the soft palate. It begins in the soft palate in 



layers in ^wo layers, which enclose between them the levator palati and 



azygos uvulse muscles. The superficial part, very thin, and situate 



immediately beneath the mucous membrane, meets in the middle 



posterior line the corresponding part of the opposite muscle ; it is also 



ioFnedlay joined b} r a slender fasciculus, which descends from the anterior 



saipingo- extremity of the cartilage of the Eustachian tube (salpingo-p/iaryn- 



/US ' qeus. Santorini : fig. 233, c). The deep or anterior layer is much 

 anterior y 

 layer is stronger, and lies between the levator and tensor palati muscles; 



its upper fibres spring from the hinder margin of the hard palate 

 and the aponeurosis of the velum, while the lower ones join those 

 of the opposite side. The two layers meet at the outer part of the 

 soft palate, and the muscle descends behind the tonsil on the side 



inserted wall of the pharynx. Spreading out below, the anterior fibres are 



rartil t a 1 ge r id inserted into tne hinder border of the thyroid cartilage, but the 



and wall of greater number end in the sub mucous tissue of the pharynx beneath 

 the inferior constrictor, the hinder ones meeting the fellow muscle 

 in the middle line. 



use; Action, The palato-pharyngeus depresses and tightens the soft 



palate, raises the larynx and lower part of the pharynx, and at the 

 same time brings together the posterior pillars of the fauces, thus 

 acting as a sphincter by which the nasal portion is separated from 



in swallow- the oral portion of the pharynx. In swallowing, the hinder pillars 

 of the soft palate, being approximated by the action of this muscle, 

 form, together with the uvula, an inclined plane, beneath which 



of saipingo- the food is directed downwards. The contraction of the salpingo- 

 9US - pharyngeus at the same time assists in opening the Eustachian 

 tube, by drawing inwards and backwards the cartilage bounding 

 its orifice. 



Azygos The AZYGOS UVUL^: (fig. 233, D ; 234, 1 ) is situated along the middle 



line of the veium near the posterior part. The muscle consists of 

 two narrow slips of pale fibres, which arise from the spine at the 

 posterior border of the hard palate, or from the contiguous aponeu- 

 rosis, and end below in the base of the uvula. Behind this muscle, 

 separating it from the mucous membrane, is the thin stratum of the 

 palato-pharyngeus. 



Action. Its fibres shorten the mid-part of the soft palate, and 

 elevate the uvula, directing that process backwards. 



