144 VISCERAL ANATOMY. 



groove by the union of its margins. A Cavity of Reserve for each tooth is 

 then formed by the closure of the secondary dental groove, from the floor of 

 which another papilla arises to form the germ of the permanent tooth. 



The dental pulps now take the forms of teeth, a thin lamina of dentine 

 appears and increases from without inward, the enamel organ and membrane 

 are formed, and when calcification has advanced sufficiently, the pressure of 

 the teeth causes the absorption of the gum above them, the septa ossify and 

 the eruption of the teeth occurs. The Cement is formed from the periodental 

 membrane, at a later period of life. 



THE MOUTH. 



Describe the Mouth. It is an oval cavity formed by the lips, cheeks, 

 jaws, palate and. tongue, forming the superior portion of the alimentary canal, 

 and opening posteriorly into the pharynx by the fauces. It presents the teeth 

 (already described), the tongue (to be described), and also the 

 Hard Palate, formed by the palate processes of the superior maxillary and 

 palate bones, and covered with mucous membrane ; forms the roof of the 

 mouth. 



Soft Palate, formed by 5 muscles on each side, viz., the levator palati, tensor 



palati, palato-glossus, palato-pharyngeus, and the azygos uvulae ; the 



latter forming with its fellow the Uvula, a descending muscular projection. 



Anterior Pillars of the Fattces, arch downwards and forwards to the base of 



the tongue, and contain the palato glossi muscles. 

 Posterior Pillars of the Fauces, arch downwards and backwards to the sides 



of the pharynx, and contain the palato-pharyngei muscles. 

 Isthmus Faucium,\\\z space bounded by the pillars, the free border of the 



palate, and the base of the tongue. 



Tonsils, are small, elongated, glandular bodies, situate done on each side of 

 the fauces, between the anterior and posterior pillars. Each has 12 or 15 

 F IG gs. openings on its surface leading to 



follicular depressions within the 

 gland, and lies close to the inter- 

 nal carotid artery. 



Openings of Steno^s Ducts, from 

 the parotid glands, are situated 

 internally one on each cheek, 

 opposite the 2d upper molar tooth. 

 Openings of Wharton 's Ducts, 

 from the sub-maxillary glands, 

 one at each side of the frenum of 

 the tongue. 



