Reverse squeeze occurs when gas expands in the ear, sinuses or intestines as the surrounding pressure decreases during ascent.

Reverse ear squeeze
In this case, air expands in the middle ear, causing pain. The eardrum can rupture if the pressure increases too much.

Tooth reverse squeeze
Fillings, decay, dental infections, or recent extractions can form tiny pockets of air around a tooth. Severe dental pain occurs when the pressure increases inside the air pocket.

Sinus reverse squeeze
In this case, air expands in the sinuses, causing pain. The wall of the sinus can rupture if the pressure increases too much.

Intestinal reverse squeeze
This is caused by the expansion of gas in the intestine when the surrounding pressure is decreased during ascent.