label: Abnormal Eustachian tube morphology
label_lc: abnormal eustachian tube morphology
description: "A structural anomaly of the Eustachian tube (ET). The ET is a biomechanical valve between the nasopharynx and the middle ear. Physiologically, it controls the passive adaptation of the middle ear air pressure to the ambient air pressure primarily via direct muscular actions of the soft palate. In the closed state it protects the middle ear. Inadequate function of the ET causes middle ear ventilation disorders."