946 THE ORGAXS OF DIGESTIOX 



Actions. — (1) Tiiilitcns t\\v soft })al:ite; (2) ojicnstho Eustachian tulx' (luring 

 deulutition. 



The Azygos Uvulae — named bwause it was supposed to 1)0 a sinjile muscle. 



Origin. — ( 1 ) From the aponeurosis of tlie soft i)alate; (2) the nasal spine of 

 the palate hone. 



Insertion. — Into the uvula. 



Structure. — The muscle consists of two narrow parallel strips lying on each 

 side of the middle line of the palate. 



Nerve-supply. — Probably from the same source as tlie levator ytalati. 



Action. — To draw U]) the uvula. 



The Mucous Membrane of the soft palate is continuous with that of the 

 mouth on its anterior aspect, and with that of the nasal chamber on its posterior 

 surface; its epithelium is columnar and ciliated in the vicinity of the Eustachian 

 tuI)o, but elsewhere it is squamous and not ciliated. The glands form an espe- 

 cially thick layer on its su])erior aspect. 



Arterial supply of the soft palate. — (1) Ascending palatine of facial; (2) 

 palatine branch of ascending pharyngeal; (3) twigs from descending palatine of 

 internal maxillary, which enter the smaller palatine canals, and are distributed to 

 the soft palate and tonsils, and communicate with the ascending palatine of the 

 facial artery; (4) lingual artery, by twigs from the dorsal branch. 



Nerves to the soft palate. — (1) Branches from Meckel's ganglion ('small or 

 posterior palatine' and 'external palatine nerve'); (2) tonsillitic branches of 

 glosso-pharyngeal nerve; and (3) the nerves supplying the muscles. 



The TONSILS (figs. 507 and oGO) are two bodies situated one in each of the 

 recesses between the anterior and posterior pillars of the fauces and beneath a small 

 fossa, the supra-tonsillar recess, which is the remains of the second visceral cleft. 

 They are about an inch (20-25 mm.) in length, and half an inch (12-15 mm.) in 

 width and thickness; but their size is liable to considerable variation. 



On their inner surfaces are a number of puncture-like openings (twelve to fifteen 

 on each tonsil), which form the orifices of small recesses or crypts, into which 

 numerous follicles open. The mucous membrane is continued into, and forms a 

 lining for, these follicles; their walls are surrounded by an aggregation of closed 

 capsules somewhat similar to the solitary glands of the intestine, and they contain 

 a thick secretion. 



The tonsil corresponds in jjosition with the angle of the jaw; it is in relation 

 externally with the superior constrictor muscle, which separates it from the ascend- 

 ing pharyngeal artery; about one inch externally and posteriorly to it is the internal 

 carotid artery, and still more externally the internal pter^-goid muscle. 



Tlie arteries of the tonsil are five in number, viz. : — (1) Dorsalis lingua3 from 

 the lingual; (2) ascending pharyngeal from the external carotid; (3) ascending 

 palatine from the fa(;ial; (4) tonsillar from the facial; and (5) descending 2)alatine 

 from the internal maxillary. 



The veins of the tonsil form a plexus which lies upon the outer side of the 

 gland, and opens externally into the pharyngeal plexus. 



The lymphatics of the tonsil communicate with those of the dorsum of the 

 tongue, and they pass to a gland which lies near" the angle of the jaw. 



The nerves of the tonsil are branches of the fifth and glosso-pharyngeal. 



THE SALIVARY GLA^^DS 



The three chief salivary glands are the parotid, the submaxillary (mandib- 

 ular), and the sublingual. These all pour their secretions into the cavity of the 

 mouth. 



The PAROTID GLAND is the largest of the salivary glands. It lies just below 

 and in front of the ear, and it varies from a little ox'cr Jialf an ounce to an ounce in 

 weight. 



