PALATE SALIVARY GLANDS. 653 



the uvula on each side, are two curved folds of mucous membrane, containing 

 muscular fibres, called the arches or pillars of the soft palate. 



The anterior pillar runs downwards and forwards to the side of the base of the 

 tongue, and is formed by the projection of the Palato-glossus muscle, covered by 

 mucous membrane. 



The posterior pillars are more closely approximated and larger than the anterior; 

 they run downwards and backwards to the sides of the pharynx, and are formed 

 by the projection of the Palato-pharyngei muscles, covered by mucous membrane. 

 The anterior and posterior pillars are separated below by a triangular interval, in 

 which the tonsil is lodged. 



The space left between the arches of the palate on the two sides is called the 

 isthmus of the fauces. It is bounded above by the free margin of the palate ; 

 below, by the tongue ; and on each side, by the pillars of the soft palate and 

 tonsils. 



The mucous membrane of the soft palate is thin, and covered with squamous 

 epithelium on both surfaces, excepting near the orifice of the Eustachian tube, 

 where it is columnar and ciliated. The palatine glands form a continuous layer 

 on its posterior surface and round the uvula. 



The aponeurosis of the soft palate is a thin but firm fibrous layer, attached above 

 to the hard palate, and becoming thinner towards the free margin of the velum. 

 It is blended with the aponeurotic tendon of the Tensor palati muscle. 



The muscles of the soft palate are five on each side ; the Levator palati, Tensor 

 palati, Palato-glossus, Palato-pharyngeus, and the Azygos uvula?. 



The tonsils (amygdalse) are two glandular organs, situated one on each side 

 of the fauces, between the anterior and posterior pillars of the soft palate. They 

 are of a rounded form, and vary considerably in size in different individuals. 

 Externally, the tonsil is in relation with the inner surface of the Superior con- 

 strictor, and with the internal carotid and ascending pharyngeal arteries, and 

 corresponds to the angle of the lower jaw. Its inner surface presents from 

 twelve to fifteen orifices, leading into small recesses, from which numerous follicles 

 branch out into the substance of the gland. These follicles are lined by a con- 

 tinuation of the mucous membrane of the pharynx, covered with epithelium, their 

 walls being formed by a layer of closed capsules imbedded in the submucous 

 tissue. These capsules are analogous to those of Peyer's glands ; they contain a 

 thick grayish secretion. 



The arteries supplying the tonsil are the dorsalis lingua? from the lingual, 

 the ascending palatine and tonsillar from the facial, the ascending pharyngeal 

 from the external carotid, and the descending palatine branch of the internal 

 maxillary. 



The veins terminate in the tonsillar plexus, on the outer side of the tonsil. 



The nerves are derived from the fifth, and from the glosso-pharyngeal. 



THE SALIVARY GLANDS. 



The principal salivary glands communicating with the mouth, and pouring their 

 secretion into its cavity, are the parotid, submaxillary, and sublingual. 



The Parotid gland (fig. 330), so called from being placed near the ear ( rt apo, 

 near ; wj, u>roj, the ear), is the largest of the three salivary glands, varying in 

 weight from half an ounce to an ounce. It lies upon the side of the face, imme- 

 diately below and in front of the external ear. It is limited above by the zygoma; 

 below, by the angle of the jaw, and by an imaginary line drawn between it and 

 the Sterno-mastoid muscle ; anteriorly, it extends to a variable extent over the 

 Masseter muscle ; posteriorly, it is bounded by the external meatus, the mastoid 

 process, and the Sterno-mastoid and Digastric muscles, slightly overlapping the 

 former. 



Its anterior surface is grooved to embrace the posterior margin of the ramus of 

 the lower jaw, and advances forwards beneath the ramus, between the two ptery- 



