1204 



THE ORGANS OF DIGESTION 



for its limited sensibility. Around the necks of the teeth the fibroelastic portion 

 presents numerous fine papillae; and from this point it is reflected into the alveolus, 

 where it is continuous with the periosteal membrane lining that cavity. 



The Palate (palatum) forms the roof of the mouth; it consists of two portions, 

 the hard palate, about two-thirds in front, the soft palate, about one-third behind. 



The hard palate (palatum durum) (Figs. 914 and 915) is bounded in front 

 and at the sides by the upper alveolar arches and gums; behind, it is continuous 

 with the soft palate. It is formed by the palate processes of the maxilla? and the 

 palate processes of the palate bones (Fig. 72). It is covered by a dense structure 

 formed by the periosteum and mucous membrane of the mouth, which are inti- 

 mately adherent, particularly to the front and sides, by means of a layer of fibrous 



ANTERIOR 

 PALATINE CANAL 



DESCENDING 



PALATINE 



ARTERY 



FIG. 915. The palatine vault on the right side of the mucous membrane has been removed. The left side shows 

 the mucous membrane and the glandular layer. (Poirier and Charpy.) 



tissue. Along the middle line is a linear ridge or raphe' (raphe palati), which 

 terminates anteriorly in a small papilla, the incisive papilla (papilla incisiva), 

 corresponding with the inferior opening of the anterior palatine fossa. On either 

 side and in front of the raphe the mucous membrane is thick, pale in color, and 

 corrugated; these corrugations, which are composed of fibrous tissue, are the 

 palatine 1 rugae (plicae palatinae transversae). In very young children the ruga 1 

 are distinct and definite. In the aged they are indistinct. Behind, it is thin, 

 smooth, and of a deeper color; it is covered with stratified squamous epithelium, 

 and the fibrous tissue beneath it contains many mucous glands, the palatine glands 

 (glandulae palatinae). The palatine vessels and nerves lie in the fibrous tissue 

 beneath the mucous membrane. 



1 Concerning the etymology of palatal and palatine, see footnote on page 109. 



