Physiological Basis for Tubal Function Tests

The role of the tube in normal and pathological states of the middle ear is not clearly defined. The tube function is considered normal when the drum and middle ear appear normal. It is considered abnormal by implication in some states of middle ear disease. While we know that ventilation of the middle ear is necessary for normal function, we do not have the means to measure it directly. It can be done experimentally, however, by recording sound transmission through the tube which reflects the duration, amplitude, and shape of opening and closing of the tube during swallowing. Even if we had the means of making this measurement in the clinic, it would be difficult to define an adequate or inadequate opening to maintain normal air pressure behind the drum. This is because the tube, even under normal conditions, only opens occasionally during swallowing and probably with different degrees of