A text-book of the diseases of the ear for students and practitioners . ll, pit-like depression above the short process; it forms theexternal wall of a small space (Prussaks space) which communi-cates with the tympanic cavity. The height of the pars flaccidais 1|- mm., the width at the base 2 mm. 16 DISEASES OF THE EAR The first structures which attract our attention on the innersurface of the membrane are the head of the malleus and thebody of the incus connected with it; these structures lie abovethe convexity of the membrane when examined from the tympaniccavity (Fig. 17, a, h, g). The neck
A text-book of the diseases of the ear for students and practitioners . ll, pit-like depression above the short process; it forms theexternal wall of a small space (Prussaks space) which communi-cates with the tympanic cavity. The height of the pars flaccidais 1|- mm., the width at the base 2 mm. 16 DISEASES OF THE EAR The first structures which attract our attention on the innersurface of the membrane are the head of the malleus and thebody of the incus connected with it; these structures lie abovethe convexity of the membrane when examined from the tympaniccavity (Fig. 17, a, h, g). The neck of the malleus (Fig. 17, b)is found below the head, from which the handle proceeds down-wards and backwards (Figs. 16 and 17, d). In spite of its closeconnection with the membrane, it stands away so far that itappears as if it were simply lying upon its inner surface. If theincus is removed, a duplicature, described by v. Troltsch, will befound on the posterior superior segment of the membrane ; itsinferior part arises from a slightly rounded ridge of bone within d-. Fig. 17.—Internal Surface of the Left Membrana Tympani (Enlarged). a, Head of the malleus ; b, Neck of the malleus ; c, Tendou of the tensor tympaniand anterior fold of the membrana tympani; d, Inferior extremity of the handleof the malleus ; e, Anterior portion of the membrana tympani ; /, Posterior foldof the membrana tympani and chorda tympani; g, Incus ; h, Short process of theincus ; i, Long process of the incus. the sulcus, and its superior part from the posterior superiorperiphery of the annulus tympanicus (limbus membraiue tympani);it then runs anteriorly and superiorly, and attaches itself tothe posterior surface of the manubrium as far as a point belowits centre. This fold, standing away from the drum membranewith a free, concave margin, forms, with the posterior surface ofthe above-mentioned membrane, the posterior tympanic pouch(v. Troltsch)—recessus membraiue tympani posterior (Fig. 17,/); itsrela
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectear, booksubjecteardi
