400 THE MUSCLES AND FASCIA 



membrane covering its surface, the posterior pillar of the soft palate. It is sepa- 

 rated from the Palatoglossus by an angular interval, in which the tonsil is lodged. 

 tt arises from the soft palate by an expanded fasciculus, which is divided into 

 two parts by the Levator palati and Azygos uvulae. The posterior fasciculus 

 lies in contact with the mucous membrane, and also joins with the corresponding 

 muscle in the middle line; the anterior fasciculus, the thicker, lies in the soft palate 

 between the Levator and Tensor, and joins in the middle line the corresponding 

 part of the opposite muscle. Passing outward and downward behind the tonsil, 

 the Palatopharyngeus joins the Stylopharyngeus, and is inserted with that muscle 

 into the posterior border of the thyroid cartilage, some of its fibres being lost on 

 the side of the pharynx, and others passing across the middle line posteriorly 

 to decussate with the muscle of the opposite side. 



Relations. In the soft palate its posterior surface is covered by mucous membrane, from 

 which it is separated by a layer of palatal glands. By its anterior surface it is in relation with 

 the Tensor palati. Where it forms the posterior pillar of the fauces it is covered by mucous 

 membrane, excepting on its outer surface. In the pharynx it lies between the mucous membrane 

 and the Constrictor muscles. 



The Salpingopharyngeus (m. salpingopharyngeus) arises from the inferior 

 part of the Eustachian tube near its orifice; it passes downward and blends with 

 the posterior fasciculus of the Palatopharyngeus. 



In a dissection of the soft palate from its posterior or nasal surface to its anterior or oral sur- 

 face, the muscles would be exposed in the following order viz., the posterior fasciculus of the 

 Palatopharyngeus, covered over by the mucous membrane reflected from the floor of the nasal 

 fossae; the Azygos uvulae; the Levator palati; the anterior fasciculus of the Palatopharyngeus; 

 the aponeurosis of the Tensor palati, and the Palatoglossus, covered over by a reflection from 

 the oral mucous membrane. 



Nerves. The Tensor palati is supplied by a branch from the otic ganglion; the remaining 

 muscles of this group are in all probability supplied by the internal branch of the spinal accessory, 

 the fibres of which are distributed along with certain branches of the vagus through the pharyn- 

 geal plexus. 1 



Actions. During the first stage of deglutition the bolus of food is driven back into the 

 fauces by the pressure of the tongue against the hard palate; the base of the tongue is, at the 

 same time, retracted, and the larynx is raised with the pharynx, and carried forward under it. 

 During the second stage the entrance to the larynx is closed, not, as was formerly supposed, by 

 the folding backward of the epiglottis over it, but, as Anderson Stuart has shown, by the draw- 

 ing forward of the arytenoid cartilages toward the cushion of the epiglottis a movement 

 produced by the contraction of the External thyroarytenoid, the Arytenoid, and Aryteno- 

 epiglottidean muscles. . 



The bolus of food after leaving the tongue passes on to the posterior or laryngeal surface 

 of the epiglottis, and glides along this for a certain distance; 2 then the Palatoglossi muscles, the 

 constrictors of the fauces, contract behind the food; the soft palate is slightly raised by the 

 Levatores palati, and made tense by the Tensores palati; and the Palatopharyngei, by their con- 

 traction, pull the pharynx upward over the bolus of food, and at the same time come nearly 

 together, the uvula filling up the slight interval between them. By these means the food is 

 prevented from passing into the upper part of the larynx or the posterior nares; at the same 

 time the latter muscles form an inclined plane, directed obliquely downward and backward, 

 along the under surface of which the bolus descends into the lower part of the pharynx. Each 

 Salpingopharyngeus raises the upper and lateral part of the pharynx i. e., that part which is 

 above the point where the Stylopharyngeus is attached to the pharynx. 



Applied Anatomy. After operation for cleft palate the Tensor palati and Levator palati 

 retard union by causing undue tension along the line of suture. In order to overcome this 

 it is necessary to divide these muscles, and this is done by making longitudinal incisions on 

 either side, parallel to the cleft and just internal to the hamular process, in such a position as 

 to avoid the posterior palatine artery. 



1 Journal of Anatomy and Physiology, vol. xxiii, p. 523. 



2 We now know that normal deglutition can be carried out when the epiglottis is so small that it cannot coyer 

 the opening into the larynx, or when it has been removed surgically. In such cases the sphincter muscles which 

 surround the larynge.al aperture contract during swallowing and prevent the entrance of foreign bodies into the 

 larynx. 



