Зображення 00528. Tympanometric findings

A normal (type A) tympanogram (left) shows a clear peak (maximum compliance of the tympanic membrane) at an ear canal pressure equal to the tympanic cavity pressure. Pressure readings below –200 dPa (type C) indicate poor ventilation of the middle ear. A flat (type B) tympanogram (in the middle) indicates middle ear effusion. In the early phase of acute otitis media the tympanic membrane may be still mobile but the pressure is increased (right).