異型のTympanogram

UNUSUAL TYMPANOGRAMS

　Ⅰ．はじめに

　tympanometryは密閉された外耳道の圧を変化させることにより，鼓膜のcomplianceの変化を見る検査である。鼓膜のcomplianceは鼓膜，耳小骨連鎖，耳小骨筋，靱帯などのstiffnessの状態を反映しており，中耳と外耳の圧が等しい時に最大である。したがつて，tympanometryを行なうことで鼓膜の性状，耳小骨連鎖の状態，中耳腔の圧や耳管機能を知ることができる。

　また圧の変化でstiffnessが大きく変化する外耳道病変ではtympanometryは鼓膜のみならず外耳道のcompliance変化をも検出しうる。

　Tympanometry was performed in 700 patients who complained of various aural symptoms. Tympanograms from the patients with lymphangioma and Recklinghausen's disease showed unusual shapes because the canal skin was deformed by the diseases.

　Patulous eustachian tube showed a typical tympanogram, that is respiratory movements were superimposed on the tympanogram.

　A type C tympanogram changed to a diterent shape after eustachian catheterization in a patient of floppy tube, whose eardrum was partly atrophic. The original tympanogram wasobtained after repeated swallowings.

　The cause and physiological basis of unusual tympanograms were discussed.