THE SALIVARY GLAXDS. 945 



palate from the posterior or nasal to the anterior or oral surface : Immediately 

 beneath the nasal mucous membrane is a thin stratum of muscular fibres, the 

 posterior fasciculus of the Palato-pharyngeus muscle, joining with its fellow of 

 the opposite side in the middle line. Beneath this is the Azygos uvulae, consist- 

 ing of two rounded fleshy fasciculi, placed side by side in the median line of the 

 soft palate. Next come the fibres of the Levator palati, joining with the muscle 

 of the opposite side in the middle line. Fourthly, the anterior fasciculus of the 

 Palato-pharvngeus, thicker than the posterior, and separating the Levator palati 

 from the next muscle, the Tensor palati. This muscle terminates in a tendon 

 which, after winding round the hamular process, expands into a broad aponeurosis 

 in the soft palate, anterior to the other muscles which have been enumerated. 

 Finally, we have a thin muscular stratum, the Palatp-glossus muscle, placed in 

 front of the aponeurosis of the Tensor palati. and separated from the oral mucous 

 membrane by adenoid tissue. 



The tonsils (amygdcdce) 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. Exter- 

 nally the tonsil is in relation with the inner surface of the Superior constrictor, 

 which separates it from the internal carotid and ascending pharyngeal arteries. 

 It 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 continua- 

 tion of the mucous membrane of the pharynx, covered with epithelium ; around 

 each follicle is a layer of closed capsules imbedded in the submucous tissue. These 

 capsules are analogous to those of Fever's glands, consisting of adenoid tissue. 

 No openings from the capsules into the follicles can be recognized. They contain 

 a thick grayish secretion. Surrounding each follicle is a close plexus of lymphatic 

 ."essels. From these plexuses the lymphatic vessels pass to the deep cervical 

 glands in the upper part of the neck, which frequently become enlarged in affec- 

 tions of these organs. 



The arteries supplying the tonsil are the dorsalis linguae from the lingual, the 

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

 external carotid, the descending palatine branch of the internal maxillary, and a 

 twig from the small meningeal. 



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

 tonsil. 



The nerves are derived from Meckel's ganglion and from the glosso-pharyngeal. 



THE SALIVARY GLANDS (Fig. 569). 



The principal salivary glands communicating with the mouth and pouring 

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



The parotid gland, so called from being placed near the ear (~af>d, near ; ouz, 

 oroc, 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 immediately below 

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

 the angle of the jaw and by a line drawn between it and the mastoid process: 

 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 latter. 



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

 the lower jaw, and advances forward beneath the ramus, between the two Pterygoid 

 muscles and in front of the ramus over the Masseter muscle. Its outer surface, 

 slightly lobulated, is covered by the integument and parotid fascia, and has one or 

 two lymphatic glands resting on it. Its inn> / surf ace extends deeply into the neck 

 by means of two large processes, one of which dips behind the styloid process and 

 projects beneath the mastoid process and the Sterno-mastoid muscle ; the other is 



60 



