MUSCLES OF PALATE. 129 



On the left side, the mucous membrane is to be raised with great care 

 from the posterior surface of the palate, to obtain a view of the superficial 

 muscular fibres. Immediately beneath the mucous covering are some 

 fine transverse fibres of the palato-pharyngeus muscle; and beneath them, 

 in the middle line, are the longitudinal fibres of the azygos uvulae. A 

 deeper set of fibres of the palato-pharyngeus is to be followed, on the right 

 side, beneath the levator and azygos muscles. 



The student should remove next the mucous membrane from the mus- 

 cular fibres contained in the arches of the palate, and should follow these 

 upwards and downwards. In order to see them in the anterior fold, it 

 will be necessary to take the membrane from the anterior surface of the 

 palate. If the part is not tolerably fresh, some of the paler fibres may 

 not be visible. 



Aponeurosis of the soft palate* Giving strength to the velum is a thin 

 but firm aponeurosis, which is attached to the hard palate. This mem- 

 brane becomes thinner as it descends in the velum; and it is joined by 

 the tendon of the tensor palati muscle. 



The MUSCLES of the soft palate are four on each side, an elevator and 

 tensor; with the palato-glossus and paJato-pharyngeus, which act as de- 

 pressors. In addition there is a small median azygos muscle. 



The LEVATOR PALATI (fig. 29, A ) is a thick, roundish muscle, which is 

 partly situate outside the pharynx. It arises from the under surface of 

 the apex of the petrous portion of the temporal bone (fig. 30, 3 ), and from 

 the inner and hinder part of the cartilage of the Eustachian tube. The 

 fibres enter the pharynx above the superior constrictor, and then spread 

 out in the soft palate, where they join along the middle line with those 

 of the muscles of the opposite side. 



Outside the pharynx this muscle rests against the Eustachian tube. In 

 the palate it forms a stratum that reaches the whole depth of that struc- 

 ture, and is embraced by two planes of fibres of the palato-pharyngeus ( 4 ). 



Action. It tilts backwards the free edge of the soft palate towards the 

 pharynx so as to enlarge the isthmus faucium, and to shut off with the 

 contracted pharynx the nose openings. In swallowing the palate is raised, 

 and is arched over the bolus passing from the mouth to the pharynx. For 

 its action on the Eustachian tube, see Tensor palati. 



The TENSOR vel CIRCUMFLEXUS PALATI (fig. 29, B ) arises like the 

 preceding outside the pharynx, and is a thin riband-like band, situate 

 between the internal pterygoid plate and muscle. About one inch and a 

 half wide at its origin, it is attached to the slight depression (scaphoid 

 fossa) at the root of the internal pterygoid plate, to the outer and forepart 

 of the Eustachian tube, and still further out to the spinous process of the 

 sphenoid, and the vaginal (tympanic) process of the temporal bone. In- 

 feriorly the fleshy fibres end in a tendon which, entering the pharynx 

 between the attachments of the buccinator muscle, is reflected round the 

 hamular process (fig. 30, 2 ), and is inserted into about one-third of an inch 

 of the posterior border of the palate, viz., from the central spine to a pro- 

 jecting point; and interiorly into the aponeurosis of the velum. 



As the tendon winds round the bone, it is thrown into folds; and be- 

 tween the two is a bursa. In the soft palate it lies beneath the levator 

 muscle. The P^ustachian tube is directed inwards between this muscle 

 and the preceding. 



Action. Acting from the skull the muscle will fix and make tense the 

 9 



