364 



MUSCLES AND FASCIAE. 



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

 mucous membrane. 



Nerves. The muscles of this group are supplied by branches from the pharyn- 

 geal plexus and glosso-pharyngeal nerve ; and the Inferior constrictor, by an addi- 

 tional branch from the external laryngeal nerve. 



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

 upwards 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 upwards and outwards 

 the sides of this cavity, the breadth of the pharynx in the antero-posterior direction 

 being increased by the larynx and tongue being carried forwards 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 

 downwards into the oesophagus. 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. Azygos Uvulae. 



Tensor Palati. Palato-glossus. 



Palato-pharyngeus. 



Dissection (fig. 157). 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 tonse, 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. 



Fig. 157. Muscles of the Soft Palate ; the Pharynx being laid open from behind. 



