THE PALATAL REGION. 329 



internal jugular vein and pharyngeal venous plexus, the glosso-pharyngeal, pneu- 

 mogastric, spinal accessory, hypoglossal, lingual, and sympathetic nerves, the 

 Middle constrictor and Internal pterygoid muscles, the Styloid process, the Stylo- 

 hyoid ligament, and the Stylo-pharyngeus. By its internal surface, with the 

 Palato-pharyngeus, the tonsil, the fibrous coat and mucous membrane of the 

 pharynx. 



The Stylo-pharyngeus is a long, slender muscle, round above, broad and thin 

 below. It arises from the inner side of the base of the styloid process, passes 

 downward along the side of the pharynx betAveen the Superior and Middle 

 constrictors, and spreads out beneath the mucous membrane, where some of its 

 fibres are lost in the Constrictor muscles ; and others, joining with the Palato- 

 pharyngeus, are inserted into the posterior border of the thyroid cartilage. The 

 glosso-pharyngeal nerve runs on the outer side of this muscle, and crosses over it 

 in passing forward to the tongue. 



Eelations. Externally, with the Stylo-glossus muscle, the parotid gland, the 

 external carotid artery, and the Middle constrictor ; internally, with the internal 

 carotid, the internal jugular vein, the Superior constrictor, Palato-pharyngeus, and 

 mucou? membrane. 



Nerves. The Constrictors are supplied by branches from the pharyngeal 

 plexus, the Stylo-pharyngeus by the glosso-pharyngeal nerve, and the Inferior 

 constrictor by an additional branch from the external laryngeal nerve and by the 

 recurrent laryngeal. 



Actions. When deglutition is about to be performed, the pharynx is drawn 

 upward and dilated in different directions, to receive the morsel propelled into it 

 from the mouth. The Stylo-pharyngei, which are much farther removed from 

 one another at their origin than at their insertion, draw the sides of the pharynx 

 upward and outward, and so increase its transverse diameter, its breadth in the 

 antero-posterior direction being increased by the larynx and tongue being carried 

 forward in their ascent. As soon as the morsel is received in the pharynx, the 

 Elevator muscles relax, the bag descends, and the Constrictors contract upon 

 the morsel, and convey it gradually downward into the oesophagus. Besides 

 its action in deglutition, the pharynx also exerts an important influence in the 

 modulation of the voice, especially in the production of the higher tones. 



6. Palatal Region. 



Levator palati. Palato-glossus. 



Tensor palati. Palato-pharyngeus. 



Azygos uvulae. Salpingo-pharyngeus. 



Dissection (Fig. 209). Lay open the pharynx from behind by a vertical incision extending 

 from its upper to its lower part, and partially divide the occipital attachment by a transverse 

 incision on each side of the vertical one ; the posterior surface of the soft palate is then exposed. 

 Having fixed the uvula so as to make it tense, the mucous membrane and glands should be care- 

 fully removed from the posterior surface of the soft palate, and the muscles of this part are at 

 once exposed. 



The Levator palati is a long, thick, rounded muscle, placed on the outer side 

 of the posterior nares. It arises from the under surface of the apex of the petrous 

 portion of the temporal bone, and from the inner surface of the cartilaginous por- 

 tion of the Eusatchian tube ; after passing into the pharynx, above the upper con- 

 cave margin of the Superior constrictor, it passes obliquely downward and inward, 

 its fibres spreading out in the soft palate as far as the middle line, Avhere they 

 blend with those of the opposite side. 



Relations. Externally, with the Tensor palati and Superior constrictor and 

 Eustachian tube ; internally, with the mucous membrane of the pharynx ; pos- 

 teriorly, with the posterior fasciculus of the Palato-pharyngeus, the Azygos uvulae, 

 and the mucous lining of the soft palate. 



The Circumflexus or Tensor palati is a broad, thin, ribbon-like muscle, placed 

 on the outer side of the Levator palati, and consisting of a vertical and a horizontal 



