Abstract
Articular surface of otosclerotic footplates of stapes and fractured surface of normal footplates are examined under the scanning electron microscope.
1. Four stapes removed at surgery for clinical otosclerosis were examined. Three of them schow common findings as below.
a. Anterior margin of otosclerotic footplate change very spongy and have no enchondral layer which is in contact with otosclerotic focus.
b. Pathological bone marrow spaces of otosclerotic lesion are localized on the articular surface of antererior crus.
c. Otosclerotic lesion consists of pathological bone marrow spaces and irregular bony deposits, which schow sponge-like surface too. Inner surface of the marrow space is extremely smooth. On the other hand, the surface of bony deposits show gross irregularity.
2. Normal footplate is composed of two layers, an enchondral layer facing the inner ear and articular surface, and an endosteal layer facing the middle ear.
The endosteal layer consists of “Strahnenknochen” by Osterle
