Politzer's text-book of the diseases of the ear and adjacent organs : for students and practitioners / translated by Oscar Dodd ; edited by Sir William Dalby.

  • Politzer, Adam, 1835-1920.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Politzer's text-book of the diseases of the ear and adjacent organs : for students and practitioners / translated by Oscar Dodd ; edited by Sir William Dalby. Source: Wellcome Collection.

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    membrana tympani, in which macroscopically no trace of an epi- dermal layer was visible in the tympanic cavity; by the microscope it could be seen that the epidermis from the external meatus had extended over the inner wall of the tympanic cavity. The invasion of epidermis from the meatus into the tympanic cavity only produces the formation of secondary cholesteatoma, if an excessive growth of the epidermis in the external meatus occurs, to which a decided desquamation in the lining of the middle ear may be added. Another factor by which the invasion of epidermis from the exter- nal meatus into the tympanic cavity is favoured is the membranous or osseous closure of the ost. tymp. tubse, which occasionally occurs in middle-ear suppuration. As long as the tube remains open and the epithelium of the tympanic cavity is uninterruptedly connected with that of the tube and the naso-pharynx, the entrance of the epidermis from the external meatus is met by a marked resistance. If the connection is broken, through the closure of the tube, the weaker epithelium of the tympanic cavity loses its resistibility and the epidermis from the meatus enters so much more easily, as in such cases an epidermic change of the middle-ear mucous membrane follows. The larger the defect in the membrana tympani so much easier will the epidermis from the meatus penetrate into the tympanic cavity. In central perforations the extension is more difficult than in peripheral perforations. This is shown by the frequent occurrence of invasion of cholesteatoma in small openings in the posterior superior quadrant of the membrana tympani or in perforations of Shrapnell's membrane (Morpurgo, Bezold). In no form of perforation of the membrane could I follow the ex- tension of the epidermis from the meatus in the living, so certainly as in the destruction of the membrana Shrapnelli. The invasion through the peripherally situated opening in the membrane in this region occurs more easily, as from the upper wall of the meatus ex- tensive growth of the cutis and epidermis takes place in the direction of the membrana Shrapnelli to the membrana tympani. The growth of the epidermis is more extensive here than on the other walls of the meatus. The method of invasion for cholesteatoma is not always through the perforated membrane. In a case described by me, of chole- steatoma in the mastoid process, the extension of the epidermis into the sacculated mastoid cells could be proved through a fistulous open- ing on the cortical portion of the mastoid process, and through a second fistulous opening on the posterior wall of the meatus. The size of cholesteatomata vary from that of a hemp seed to a