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Diver clearing ears Section of the human ear, the Eustachian tube is shown in colour. Ear clearing, clearing the ears or equalization is any of various maneuvers to equalize the pressure in the middle ear with the outside pressure, by letting air enter along the Eustachian tubes, as this does not always happen automatically when the pressure in the middle ear is lower than the outside pressure.
Because the glottis is closed, air cannot return to the lungs. The tongue creates an airtight seal against the upper teeth or in the rear of the mouth, preventing air from escaping. Because there is nowhere else for the air to go, it enters the eustachian tubes and the middle ear, equalizing the pressure. [4]
Variations of the maneuver can be used either in medical examination as a test of cardiac function and autonomic nervous control of the heart (because the maneuver raises the pressure in the lungs), or to clear the ears and sinuses (that is, to equalize pressure between them) when ambient pressure changes, as in scuba diving, hyperbaric oxygen ...
The pressure in the middle ear not equalizing with external (ambient) pressure, usually due to failure to clear the Eustachian tube. [31] Ears can be equalized early and often during the descent, before the stretching is painful. The diver can check if the ears will clear on the surface as a precondition for diving. [31]
Samantha Cristoforetti demonstrating the use of the Valsalva device in the Sokol space suit. The Valsalva device is a device used in spacesuits, some full face diving masks, and diving helmets to allow astronauts and commercial divers to equalize the pressure in their ears by performing the Valsalva maneuver inside the suit without using their hands to block their nose.
Middle ear barotrauma (MEBT), also known to underwater divers as ear squeeze and reverse ear squeeze, is an injury caused by a difference in pressure between the external ear canal and the middle ear. It is common in underwater divers and usually occurs when the diver does not equalise sufficiently during descent or, less commonly, on ascent.
Divers must avoid injuries caused by changes in pressure. The weight of the water column above the diver causes an increase in pressure in proportion to depth, in the same way that the weight of the column of atmospheric air above the surface causes a pressure of 101.3 kPa (14.7 pounds-force per square inch) at sea level.
The tensor veli palatini muscle (tensor palati or tensor muscle of the velum palatinum) is a thin, triangular muscle of the head that tenses the soft palate and opens the Eustachian tube to equalise pressure in the middle ear.