CHAPTER XXIII. 



THE MOUTH AND TONGUE. 



BY D. BRYSON DELAY AN, M.D. 



Curator of the New York Hospital, New York City ; Member of the American Laryn- 



gological Association. 



WITH the exception of a few remarkable modifications, the 

 structure of the mucous membrane of the buccal cavity is the 

 same throughout. 



The tunica propria consists of fibrillated connective tissue, 

 made up of tolerably minute bundles of intertwining filaments. 

 Between these appear many delicate, elastic fibres. Toward 

 the epithelium this structure becomes less distinct, and an ex- 

 ceedingly delicate, filamentous network is developed. The con- 

 nective-tissue cells with their nuclei, on the other hand, become 

 more marked. The surface of the tunica propria contains 

 many slender papillae, which penetrate more or less deeply 

 into the epithelial covering. They have, also, the above-men- 

 tioned filamentous structure, but contain few cellular elements. 



The transition of the tunica propria into submucous connec- 

 tive tissue is, in general, hardly perceptible. The latter, how- 

 ever, contains fewer elastic filaments and broader bundles of 

 connective tissue. The epithelium lining the buccal cavity is, 

 throughout, stratified pavement. The mucous membrane of 

 the mouth varies in different regions as to the thickness of its 

 different strata, the height of its papillae, and the condition of 

 the submucous tissue. It is thickest and firmest in the gums 

 and near the palate particularly in the posterior section of the 

 hard palate and thinnest in its reduplications, e.g., the froe- 

 num linguae, glosso-epiglottic fold, and the pillars of the fau- 

 ces. Its firmness in the above places is due to the density of 

 the submucosa, which forms, with the underlying periosteum, 

 one compact mass of connective tissue. 



