A text-book of the diseases of the ear and adjacent organs . y that gentle elevation ofthe inferior wall towards the anterior, which is situated below the ostium * This anomaly, which is designated by Hyrtl as spontaneous dehiscence of thetegmen tympani, is probably due to arrested development. IOSTEKIOK WALL OF THE TYMPANIC CAVITY. 23 t vmpanicum tubae. Its surface usually presents ridges and hollows,* but isoften smooth and bulged forward towards the tympanic cavity by the adjoin-ing fossa jugularis. Its thickness varies in the same manner as that of tin-superior wall. The proximity of the i
A text-book of the diseases of the ear and adjacent organs . y that gentle elevation ofthe inferior wall towards the anterior, which is situated below the ostium * This anomaly, which is designated by Hyrtl as spontaneous dehiscence of thetegmen tympani, is probably due to arrested development. IOSTEKIOK WALL OF THE TYMPANIC CAVITY. 23 t vmpanicum tubae. Its surface usually presents ridges and hollows,* but isoften smooth and bulged forward towards the tympanic cavity by the adjoin-ing fossa jugularis. Its thickness varies in the same manner as that of tin-superior wall. The proximity of the inferior wall of the tympanic cavity to the fossajugularis is worthy of remark, because a fatal phlebitis with thrombosis in thebulbus vena? jugularis is often brought about by caries of this wall. d. Posterior Wall of the Tympanic Cavity. The height of the posterior wall, rising abruptly from the floor of the tym-panic cavity (Fig. 23), amounts to several millimetres. Above it there isa great triangular aperture, which is the means of communication between. Fig. 23.—View of the Posterior Wall of the Tympanic Cavity. , //, Superior and inferior walls of the meatus ; c, Superior wall of the tympanic cavity ; d, Protuberance underneath the eminentia stapedii, caused by the superior extremity of the styloid process ; e, Posterior wall ; f, Entrance into the mastoid process ; a, Eminentia stapedii ; h, Canalis Fallopiae ; i, Interior meatus. the tympanic cavity and the mastoid process. In the inferior angle of thisaperture a saddle-shaped notch will be found, in which rests the short processof the incus. From the surface of the posterior wall there arises a smallD->K)Us projection, directed forwards, on the pointed extremity of delicate and rounded aperture is visible. This is the eminentia pyra-nridaKa in), which is connected with the Fallopian canal by one or more * In this wall also dehiscences have been observed similar to those in the superiowall (Friedlowskv). 24
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Keywords: ., bookcentury1800, bookdecade1890, booksubjecteardiseases, bookyear
