Q. What is the auditory tube and its function?

Auditory tube (Eustachian tube) connects each middle ear to the throat. This tube conducts air between tympanic cavity and outside of the body by way of the throat and mouth. It also helps sustain equal air pressure on both sides of the eardrum, which is essential for normal hearing. Function of auditory tube can be experienced during rapid change in altitude. As a person moves from a high altitude to a lower one, air pressure on the outside of the membrane becomes greater and greater. Consequently, eardrum may be pushed inward, out of its normal position, and hearing may be impaired. When air pressure difference is great enough, some air may force its way up through auditory tube into the middle ear. This allows pressure on both sides of eardrum to equalize, and drum moves back to its regular position. An individual generally hears a popping sound at this time, and normal hearing is restored. A reverse movement of air occurs when a person moves from a low altitude to a higher one.