Handbook of diseases of the ear : for the use of students and practitioners / by Urban Pritchard.

  • Pritchard, Urban.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: Handbook of diseases of the ear : for the use of students and practitioners / by Urban Pritchard. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    39/318 (page 17)
    1. The Pneumatic, in which the whole or nearly the whole of the process is occupied by air-cells communicat- ing freely with one another and with the antrum, and lined with mucous membrane continuous with that found in the latter cavity. 2. The Diplo'etic, in which the cells are very small, do not contain air, but are filled with diploetic tissue. 3. The Pneumo-diplo'etic, in which there is an admixture of the two preceding types. 4. The Sclerosed, in which the whole process is made up of compact bone with neither air-cells nor diploetic tissue. Surgically and pathologically the condition of the mastoid process is of great importance. In suppurative inflammation of the attic for instance, if the process is of the pneumatic variety, and especially if the air-cells are large and communicate freely with one another, the pus can readily find its way to the surface; but on the other hand in the diploetic, and still more in the sclerosed types, the obstruction to the passage of the pus is so considerable that there is a very great risk of the inflammatory process extending inwards to the cranial cavity. Although the tympanum (including the attic) and antrum may thus be considered as forming, anatomically, one continuous cavity, this cavity must be regarded as divided pathologically into two by the malleus, incus, &c, in the manner described on page 11 ; so that a per- foration of the membrana tympani below the level of the ossicles leads directly into the anterior cavity or tym- panum proper and does not involve the antrum, whereas a perforation above the ossicles (in the membrana flaccida) is a more serious matter, leading as it does into the posterior or antro-attic cavity which is much less accessible to treatment. c