The Eustachian (auditory) tube is tube the connects the nasopharynx with the Mild ear. The Eustachian tube is approximately 3-4 cm long and its diameter is only 1-2 mm.

Eustachian Tube Function

Ventilatory Function or Biofunction: It maintains the same pressureon both sides of the tympanic membrane, i.e. it equalizes ear pressure in the tympanic membrane with ambient pressure stop it is important for the proper sound conditions. For example, if the atmospheric pressure increases, the air passes through the Eustachian tube from the nasopharynx to the tympanic membrane. if the atmosphere pressure decreases, then the air pressure passes, vice versa, from the tympanic membrane to the nasopharynx.

Drainage Function. it clears secretions from the middle ear cleft.

Protective Function: The secretion produced by ceruminous glands has antimicrobial activity and contains Ig A that plays critical role in mucosal immunity.

Eustachian Tube Dysfunction (ETD)

The Eustachian Tube Dysfunction (ETD) is a common problem that accompanies, as a rule, various acute respiratory viral infection, acute rhinitis and sinusitis caused by allergies as well. ETD leads to conductive hearing loss and secretory otitis media. It should be noted that children under 7 years of age are more predisposed to the Eustachian tube dysfunctions because of there anatomic features. The Eustachian tube in children is shorter, straighter and it muscle contraction mechanism is less controlled.

If there is the eustachian tube dysfunction, the mild ear is less protected from pressure drops, for example, while in flight or dividing. If the dysfunction is severe, the probability of barotrauma is increased which can lead to tympanic membrane rupture, conductive hearing loss and, rarely labyrinthine fistula.

To evaluate the Eustachian tube, function the following tests are used:

1. Tympanometry Tests: The significant shift of tympanogram pressure peak to positive or negative pressure (compared with normative values) means the Eustachian tube the dysfunction.
2. The Toynbee Tests: This test is designed to introduce negative pressure into middle ear via the eustachian tube using classic Toynbeemaneuver, a post-test tympanometry is recorded. Tubal Opening is indicated by a negative shift in the tympanogram.
3. The Valsalva Tests: This test is designed to introduced positive pressure into middle ear via the Eustachian tube using classic Valsalva maneuver. Positive pressure is introduced into the middle ear by holding nose and gently blowing air into the posterior nasopharynx.
4. A pretext tympanogram is recorded (the tympanogram after Toynbee test could be used as a pre-test one) After the Valsalva maneuver a post-test tympanogram is recorded. Tubal Opening is indicated by a positive shift in the tympanogram.