1252 A MANUAL OF ANATOMY 



The muscle, which is round and fleshy, passes over the upper 

 border of the superior constrictor and through the pharyngeal 

 aponeurosis. At its origin it is closely related to the membranous 

 portion of the Eustachian tube. 



Tensor Palati — Origin. — (i) The scaphoid fossa at the root of 

 the internal pterygoid plate of the sphenoid ; (2) the spine of the 

 sphenoid ; and {3) the outer side of the Eustachian tube. 



Insertion. — (i) The transverse ridge on the under surface of the 

 horizontal plate of the palate bone, near the posterior border ; and 

 (2) the aponeurosis of the soft palate. 



Nerve-supply. — A branch from the otic ganglion. Two views are 

 maintained as to the source from which the nerve-fibres are derived. 

 One view is that they come from the inferior maxillary division of 

 the fifth cranial nerve, through the branch to the internal pterygoid 

 muscle, which branch furnishes motor fibres to the ganglion. 



The nerve-supply of the tensor palati muscle is explained as follows: The 

 Eustachian tube is developed from the first visceral cleft; the tensor palati 

 muscle lies in front of the Eustachian tube, and is consequently associated 

 with the first visceral, or mandibular, arch; and the nerve of that arch is the 

 inferior maxillary division of the fifth cranial nerve. 



The muscle at first descends vertically as a flat fleshy band 

 between the internal pterygoid plate and the internal pterygoid 

 muscle, being in close contact with the mesial surface of the latter. 

 As it ^^roaches the hamular process it ends in a tendon, which 

 turns round that process, a synovial bursa intervening, and then 

 passes horizontally inwards, expanding as it does so. From the fact 

 that the muscle is bent around the hamular process it has been 

 called the circumflexus palati. 



Action. — (i) To make tense the soft palate, and (2) to draw 

 downwards and backwards the margins of the cartilage of the 

 Eustachian tube, and so open the tube during deglutition. (See 

 action of levator palati.) The muscle comes into play during the 

 second stage of deglutition. 



Sensory Nerves. — ^These are (i) the posterior and external palatine 

 nerves from Meckel's ganglion, and (2) the tonsillitic branches of 

 the glosso -pharyngeal. 



Arteries. — ^The soft palate is supplied by the following arteries : 

 (i) the inferior or ascending palatine of the cervical portion of the 

 facial ; (2) the palatine branch of the ascending pharyngeal ; and (3) 

 the posterior and external branches of the descending palatine 

 artery from the internal maxillary, which descend in the posterior 

 and external accessory palatine canals. 



Relation of Structures in the Soft Palate. — Supposing the soft 

 palate to be transfixed from its buccal to its pharyngeal surface, the 

 following structures would be pierced in the order stated : (i) the 

 mucous membrane covering the buccal surface, (2) the layer of 

 closely-set racemose glands, (3) the palato-glossus, (4) the lower 

 layer of the palato-pharyngeus, (5) the palatal aponeurosis and 

 tensor palati, (6) the levator palati, (7) the azygos uvulae, (8) the 

 upper layer of the palato-pharyngeus, and (9) the mucous membrane 

 covering the pharyngeal surface. 



