Simple subcortical mastoidectomy is an operation for the posterior drainage of the vault and for the exenteration of all the diseased cells of the mastoid process without the removal of the outer mastoid cortex, the posterior bony wall of the canal being used as a new method of approach.
Before describing this operation in detail, a simple review of the well known anatomic and pathologic facts which have a direct bearing on the procedure may be of value. These are:
1. The external wall of the mastoid cortex is a much denser and thicker structure than the anterior wall of the mastoid cortex, which enters into the formation of the posterior bony wall of the canal.
2. The majority of the mastoid cells are situated between the posterior bony wall of the external auditory canal and the thin bony plate covering the lateral sinus.
3. The aditus and antrum are