Histopathology of the tensor tympani muscle in otitis media.

Involvement of the tensor tympani muscle (TTM) and tendon in otitis media have been suggested both clinically and experimentally. Extensive postmortem histopathological studies of the human TTM in cases with known otitis media have not been done. One-hundred-five human temporal bones with and without otitis media were evaluated using light microscopy to determine the pathological changes of the TTM and tendon. Fatty cell infiltration and degenerative changes of the muscle fibers were observed in non-otitis and otitis media groups, but were greater in those cases with otitis media. Inflammatory cell infiltration and fibroblastic reactions occurred more often in chronic and purulent otitis media, and hypercontracted fibers were more frequent in serous and chronic otitis media. This study indicates that the human TTM and tendon are pathologically involved in the inflammatory process of otitis media.