THE MUSCLES OF THE PHARYNX 165 



aponeurosis of the palate, and posteriorly it meets its fellow 

 under cover of the azygos uvulae. 



Circumflex, or Tensor Palati. Origin, scaphoid fossa at the 

 root of the internal pterygoid plate, spine of the sphenoid, and 

 outer side of the Eustachian tube; descends vertically and 

 internally to the internal pterygoid muscle; its tendon turns 

 around the hamular process, where there is a bursa, then passes 

 horizontally to its insertion into the transverse ridge of the 

 palate bone and aponeurosis of the soft palate. 



From before backward in the soft palate are the palato- 

 glossus, tensor palati, anterior part of the palatopharyngeus, 

 levator palati, azygos uvulae, posterior part of the palato- 

 pharyngeus, and mucous membrane. 



Nerves. Sources not fully determined; tensor palati through 

 otic ganglion from the third division of the fifth; levator palati, 

 azygos uvulae, palatoglossus, and palatopharyngeus probably 

 by the bulbar portion of the spinal accessory nerve through 

 the pharyngeal plexus. 



Actions. The constrictors are nearly immovable behind, 

 and so carry back the anterior wall, the hyoid bone and larynx 

 being carried up and back by the obliquity of the two lower 

 constrictors. The upper part of the superior constrictor can- 

 not act directly upon the food, as it is attached at both ends 

 to immovable parts. The stylo pharyngeus is the chief elevator 

 of the pharynx and larynx; the palatoghssi depress the soft 

 palate, elevate the tongue, and shut off the mouth cavity 

 from the pharynx; the palatopharyngei depress the soft palate, 

 raise the pharynx, and bring the posterior pillars together; 

 the azygos uyulce raises and shortens the uvula; the levator 

 palati raises the palate; the tensor palati tightens and sup- 

 ports the palate against the pull of other muscles and opens 

 the Eustachian tube in deglutition. Some hold that the tube 

 is closed in deglutition by the levator palati pressing its floor 

 against its upper and outer wall. The first stage of deglutition 

 is effected by the mylohyoid, styloglossus, and palatoglossus 

 pressing the tongue against the palate; the hyoid is also raised 

 by its elevators; the larynx is then carried up beneath the 

 hyoid by the thyrohyoid and stylopharyngeus, the root of 

 the tongue is drawn back by the styloglossi and the epiglottis 

 pressed down; at the same time the soft palate is raised and 

 fixed by its proper muscles; the posterior pillars and uvula 



