What occurs when a diver ascends without equalizing ear pressure?

When a diver ascends without equalizing ear pressure, ear blockage occurs due to the pressure imbalance between the external environment and the middle ear. During a dive, as a diver descends, the water pressure increases, causing the eardrum to be pushed inward if the pressure on either side is not equalized. As the diver starts to ascend, the pressure decreases, which may cause a situation where the pressure inside the middle ear is greater than the pressure outside.

If the diver does not equalize the pressure by techniques such as swallowing, yawning, or using the Valsalva maneuver, the eardrum cannot respond appropriately to reduce that pressure difference. This leads to a sensation of blockage or fullness in the ear, as the eardrum remains tense or stretched, which may also result in discomfort.

Other options, while they may be related to diving, do not directly result from the failure to equalize during ascent. Sinus pain typically arises from pressure issues in the nasal cavities, decompression sickness relates to nitrogen bubbles forming due to rapid ascent, and ear rupture refers specifically to a tear in the eardrum due to excessive pressure differences that can occur if equalization fails severely or too frequently.