. The science and practice of dental surgery. terior border of thejaw, in front of the pterygo-maxillary the growth of the sinus backwards and down-wards, the posterior or zygomatic border of thesuperior maxilla, containing the permanentmolars, is thrust downwards into the alveolarborder, the molar teeth being thus, one afteranother, brought into position. The expansion of the maxillary sinus,although it is developed as a diverticulum fromthe respiratory tract, is due only to a slightextent, if at all, to any respiratory or otherphysical pressure exerted by tlie air within itscavity
. The science and practice of dental surgery. terior border of thejaw, in front of the pterygo-maxillary the growth of the sinus backwards and down-wards, the posterior or zygomatic border of thesuperior maxilla, containing the permanentmolars, is thrust downwards into the alveolarborder, the molar teeth being thus, one afteranother, brought into position. The expansion of the maxillary sinus,although it is developed as a diverticulum fromthe respiratory tract, is due only to a slightextent, if at all, to any respiratory or otherphysical pressure exerted by tlie air within itscavity. Its expansion is the result of growthin the strictest sense of the term, viz. by anosteoclastic of bone beneath itsmucous lining, and an osteoblastic depositbeneath the periosteum covering the outersurface of the jaw. Its growth, however, ispeculiarly adapted for the purpose of makingroom for, and bringing into position, the uppermolar teeth. The postero-superior angle of the maxillarysinus, forming the anterior boundary of the. Fig. 93.—Illustrating the growth of the maxiUarysinus in the human jaw. For convenience ofrepresentation the pre-maxillary part of the jawis taken as the fixed point during growth. Fourstages in the growth of the sinus are shown :(1) At Birth, the outline of the jaw of a newly bornchild being shown stippled with the sinus internalto the second molar; (2) at the 9th year; (3)at the 15th year; (4) in the adult. , Sphenoidalsinus; , Spheno-maxillary fossa, with theSpheno-palatine opening. (Nat. size.) (Keith:Brit. Jour, of Dent. Sci.) (1) at birth, (2) at the ninth year, (3) at thefifteenth year, and (4) in the adult. For thepurposes of representation, that part of the jawwhich carries the milk teeth is taken as thefixed point. The jaw of the newly born child, 59 drawTi to scale, is placed over the alveoli ofthe teeth which succeed them in the adultjaw. It vtWl be seen from the diagram howthe development of the sinus lifts the orb
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectdentistry, bookyear19
