The Eustachian tube (ET) is a narrow tube that connects middle ear space, located behind the tympanic membrane (or ear drum) to the nasopharynx (the space at the back of the nasal passages. This tube serves to equalize the pressure in the middle ear space with external atmospheric pressure. In addition, the tube drains mucus and secretions from the middle ear space.
Mostly, the ET remains closed. It opens when a person swallows, chews or yawns. As it opens, the pressure equalizes and mucus may drain.
When ET cannot perform these functions well, the condition of Eustachian tube dysfunction (ETD) results. Patients with ETD describe ear fullness, hearing loss, tinnitus (ringing sensation) and even dizziness. Many patients with ETD report that they feel as if they are “under water,” and that they cannot clear that their ears.