中耳真珠腫発症における鼓室隔膜の役割

抄録

For the development of middle ear cholesteatoma, closing of the ventilative route via the supratubal recess in the tympanic diaphragm is indispensable. Closure of the eustachian tube by a acute otitis media results in negative pressure in the whole middle ear cavity, and the tympanic isthmus route is closed by the retracted tympanic membrane and ossicles in the middle ear of all people.
In the ear with an open supratubal recess route, which is usual in the normal ear, the atticomastoid cavity returns to normal pressure after the re-opening of the eustachian tube, and the Shrapnell's membrane stays in the normal position.
In an ear with a closed supratubal recess route, which is usual in an ear with cholesteatoma, the atticomastoid cavity stays under negative pressure even after the re-opening of the eustachian tube, and the Shrapnell's membrane retracts into the epitympanic cavity, developing into cholesteatoma.