During ascent, a diver who cannot equalize the ears could experience which condition?

• A. nasal fracture
• B. decompression sickness
• C. a block or reverse block
• D. air embolism

Answer: (C)

As you ascend, outside water pressure drops, so the middle ear must vent air to stay in balance with the surroundings. If you can’t equalize, a mismatch forms across the eardrum.

If the middle ear stays at higher pressure than the outside because air can’t escape, the eardrum is pushed outward toward the ear canal. This is experienced as a blocked, painful ear and can lead to damage—often called a block.

If air vents out too readily or suction pulls air from the middle ear, the pressure in the middle ear drops below ambient, creating a relative vacuum. The eardrum can be drawn inward, causing pain again—referred to as a reverse block.

In both cases, failure to equalize during ascent leads to ear barotrauma.