A text-book of the diseases of the ear and adjacent organs . Fig. 266.—Sagittal Saw-cut, 5 mm. medi-ally from the External Opening of theOsseous Meatus on the macerated Tem-poral Bone of an Adult. (Right Side.) v, Anterior lower wall of the osseous meatusbelonging to the pars tymp. ; c, Pneumaticcell-spaces of the middle ear, situated alongthe posterior upper wall of the meatus ; o,Upper edge of the pyramid ; s, Sin. sig-moideus ; st, Proc. Fig. 267.—Sagittal Section, 3 mm. medially from the previous , Anterior lower wall of the meatus ; an, Lateral portion of the antrum mast
A text-book of the diseases of the ear and adjacent organs . Fig. 266.—Sagittal Saw-cut, 5 mm. medi-ally from the External Opening of theOsseous Meatus on the macerated Tem-poral Bone of an Adult. (Right Side.) v, Anterior lower wall of the osseous meatusbelonging to the pars tymp. ; c, Pneumaticcell-spaces of the middle ear, situated alongthe posterior upper wall of the meatus ; o,Upper edge of the pyramid ; s, Sin. sig-moideus ; st, Proc. Fig. 267.—Sagittal Section, 3 mm. medially from the previous , Anterior lower wall of the meatus ; an, Lateral portion of the antrum mast. ; c, Pneumatic cell-spaces ; o, Upper edge of the pyramid ; h, Its posterior edge. The thickness of the posterior wall of the meatus at that part correspondingto the lateral portion of the antrum is very variable ; it is usually thicker inpneumatic than in diploetic or compact mastoid processes. When theposterior wall of the meatus is very thick, it is possible to chisel this awaywithout opening the lateral portion of the antrum. The median portion ofthe antrum, which goes into the attic without any sharp limitation, lies abovethe inner portion of the upper wall of the meatus. The external wall of thisportion of the antrum, closing it off from the tympanic cavity, is partiallyformed by the posterior portion of the margo tympani of the attic. The wallof the meatus is much thinner here, and is always opened by chisellingaway this portion of th
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Keywords: ., bookcentury1800, bookdecade1890, booksubjecteardiseases, bookyear
