Pathological anatomy
Owing to the markedly benign nature of the disease it was not until 1932, when Ballance and Duel 4 proposed decompression of the facial nerve in cases of Bell's palsy, opening the Fallopian canal from the stylomastoid foramen to the lateral semicircular canal and splitting the nerve sheath, that an opportunity was offered to inspect the nerve and its surroundings
in view. By this examination new ways were paved for the study of the disorder.
The alterations observed in the nerve, in the mastoid cells, and in the Fallopian canal shall be described separately.