THE HEAD AND NECK 



1249 



anterior and posterior pillars of the fauces. Each posterior pillar 

 belongs to the postero-inferior border of the soft palate, and it 

 sweeps outwards, downwards, and backwards on the lateral wall of 

 the pharynx. It is due to the palato-pharyngeus muscle. Each 

 anterior pillar belongs to the buccal surface of the soft palate, 

 and it sweeps outwards, downwards, and forwards to the back part 

 of the side of the tongue. It is produced by the palato-glossus 

 muscle. Between the diverging cinterior and posterior pillars, on 

 either side, there is a triangular interval, which is occupied by the 

 tonsil. The passage which leads from the buccal cavity into the 

 pharynx is called the fauces or isthmus faucium. It is somewhat 

 constricted, and is bounded above by the soft palate, below by the 



Descending Palatine Artery 



Palato-pharyngeus ^ ^ 

 Palato-glossus 



Posterior Wall of PhatjTuc •'y 



Palatal Raph« 



Uvnla 



'1^^- Post. Pillar of Fauces 



' Ant. Pillar of Fauces 

 - Tonsil 



Dorsum of Tongue 



Fig. 510. — The Buccal Cavity and Isthmus Faucium. 

 (The Maxillae axe widely separated), 



back part of the dorsum of the tongue, and on either side by the 

 anterior pillar of the fauces. 



The buccal surface of the soft palate presents a faint mesial 

 raphe. 



Structure. — ^The soft palate is composed of a double fold of mucous 

 membrane, which contains between its two layers an aponeurosis, 

 muscles, and many racemose glands, with bloodvessels and nerves. 

 The mucous membrane on the buccal surface presents, as stated, a 

 median raphe, which is continuous with that on the mucous 

 membrane of the hard palate, and along which the originally 

 separate halves of the soft palate unite. On the buccal surface and 

 along the postero-inferior border it is covered by stratified squamous 



79 



