0.52 



PHARYNX. 



the internal pterygoid plate, but of sufficient 

 breadth to extend beyond its posterior edge, 

 and terminates in a tendon which winds round 

 the hamular process; it is here retained in its 

 situation by a small ligament and is surrounded 

 by a synovial capsule to facilitate its move- 

 ments. The tendon now alters its direction, 

 for suddenly expanding into a thin but strong 

 aponeurosis it spreads horizontally forwards and 

 a little upwards to be inserted into the whole of 

 the posterior border of the palatine process of 

 the palate bone and into its posterior nasal 

 spine, uniting with the tendon from the oppo- 

 site side in the median line. It is in relation, 

 so far as regards the vertical portion of the 

 muscle, by its outer surface with the internal 

 pterygoid, and by the inner with the internal 

 pterygoid plate and the superior constrictor 

 muscle of the pharynx. The horizontal tendons 

 of these muscles form a firm aponeurotic ex- 

 pansion in the substance of the velum, which, 

 when tightened by the contraction of the ver- 

 tical muscular fibres, affords a powerful resisting 

 surface to the upward pressure of the food while 

 being thrust by the tongue through the isthmus. 



The levator palati or peristaphylinus internus 

 (petro-staphylin. Chauss.) is a flat and narrow 

 muscle, and commences by a thin tendinous 

 and fleshy origin which is attached to the 

 under rough surface of the petrous portion of 

 the temporal bone and neighbouring part of the 

 cartilaginous portion of the Eustachian tube on 

 its inner side ; from thence it descends, resting 

 upon the cephalo-pharyngeal aponeurosis, then 

 slips beneath the upper edge of the superior 

 constrictor muscle, and passes upon its internal 

 surface to reach the palate; the muscle now 

 takes a more horizontal direction inwards, and 

 expanding spreads its fibres in the substance of 

 the velum to unite with its fellow from the 

 opposite side in the median line, and is also 

 inserted into the posterior border of the ex- 

 panded tendon of the circumflexus palati. The 

 insertions of the levator and circumflexus palati 

 muscles on either side form a thin stratum, 

 tendinous in front and muscular behind, 

 through the whole extent of the soft palate. 

 The levator palati in its vertical course is re- 

 lated by its outer surface to the Eustachian 

 tube and circumflexus palati muscle, from 

 which latter it is soon separated by the supe- 

 rior constrictor of the pharynx ; it is covered 

 internally by the pharyngeal aponeurosis and 

 mucous membrane : it is an elevator of the 

 pendulous portion of the soft palate. 



The palato-pharyngeus or pharyngo-staphy- 

 linus consists of a delicate bundle of fibres 

 contained in the fold of mucous membrane, 

 known as the posterior pillar of the fauces; it 

 expands upwards into the substance of the 

 velum and downwards into the pharyngeal 

 walls. The muscular fibres which spread in 

 the velum are very delicate and mingled with 

 those of the palato-glossus : they are situated 

 immediately beneath the levator palati muscle 

 and reach across the palate to join with fibres 

 from the muscle of the opposite side in the 

 middle line : some of the fibres are attached 

 also to the posterior edge of the circumflexus 



palati tendon : arching over the upper and 

 posterior margin of the tonsil they contract to 

 descend as a thin bundle in the posterior pillar 

 of the fauces, and again expanding pass into 

 the lateral wall of the pharynx between the 

 mucous membrane and constrictor muscles ; 

 here they meet with the fibres of the stylo- 

 pharyngeus muscle and have an attachment 

 with them to the posterior border of the thyroid 

 cartilage and to the pharyngeal mucous mem- 

 brane. The principal action of these muscles 

 is to contract the isthmus faucium, which they 

 can do superiorly almost to obliteration ; they 

 can scarcely have much effect in raising the 

 pharynx ; if this latter be the fixed point, they 

 may draw down the velum and so act as anta- 

 gonists to the levatores palati. 



The palato-glossus, or constrictor isthmus 

 faucium (glosso-staphylinus), occupies the an- 

 terior pillar of the fauces and spreads its fibres 

 in the velum with the palato-pharyngeus, then 

 descends to expand upon the side of the tongue 

 near its base, mingling its fibres with the stylo- 

 glossus muscle. They may either act upon 

 the velum by depressing it or raise the sides of 

 the tongue to it. 



Azygos uvulae or palato-staphylinus is a slen- 

 der fusiform muscle, or rather a pair of muscles 

 lying side by side : a narrow slip of tendon 

 attached to the posterior nasal spine gives 

 origin to the muscular fibres, which proceed 

 backwards and downwards in the middle line, 

 resting upon the circumflexus and levator palati 

 muscles, and are lost in the substance of the 

 uvula, which organ they shorten. 



The thickness of the soft palate is mainly 

 dependent on a dense mass of small glands, a 

 continuation in short of the series already de- 

 scribed as occupying the structure of the pala- 

 tine membrane. They form an extremely thick 

 layer anteriorly, but as the velum thins to its 

 posterior free border, so these glands become 

 the more scattered as they are traced backwards; 

 they lie between the muscles and the mucous 

 membrane investing the under surface of the 

 velum ; a few also are scattered beneath the 

 mucous membrane covering its upper surface, 

 and a larger proportion of them in the sub- 

 stance of the uvula, its bulk being chiefly 

 formed by them. 



The tonsils or amygdalae (a^wyJa^Ea) are 

 lodged in the interval between the pillars of 

 the fauces : they are almond-shaped, with their 

 larger extremities directed upwards, but vary 

 in size in different individuals. They appear 

 to consist of an assemblage of mucous glands, 

 whose excretory ducts terminate in small sacs 

 that are imbedded in the substance of the tonsil, 

 and which open by larger or smaller orifices 

 upon the surface of the mucous membrane. 

 When the tonsils are inflamed these sacs exude 

 a whitish secretion, which has some resemblance 

 to an ulcer on their surface. The palato-glossus 

 descends in front of and the palato-pharyngeus 

 behind these organs ; they are supported ex- 

 ternally by the superior constrictor muscle, and 

 are covered upon their internal surface by the 

 mucous membrane of the mouth. In inflam- 

 matory enlargements of the tonsil it is closely 



