The air in the<unk>  decreases in volume during a dive, and that causes negative pressure on the covered area of the face.
Occurs when air is not added to facemask during scuba diving descent to equalize the negative pressure.
Otic barotrauma
Pulmonary barotrauma
Sinus barotrauma<unk> 
Barodentalgia (trapped dental air causing<unk> 
Pascals Law applies to the diving body (without air filled areas such as lungs) states that the pressure applied to any part of the enclosed liquid will be transmitted equally in all directions through the liquid.
Boyles Law applies to the diving body's air filled areas such as lungs, sinuses, middle ear, and states that the volume and pressure of a gas at a given temperature are inversely related.
At 2 ATA (10m/33ft) a given gas would be 1/2 it's volume, at 3 ATA (20m/66ft) it would be 1/3 it's volume and so on.
At 2 ATA (10m/33ft) a given gas would be 1/2 it's volume, at 3 ATA (20m/66ft) it would be 1/3 it's volume and so on.
Mask squeeze
Barotrauma of descent
Body packing
Otic barotrauma
Mirror laryngoscopy
Pulmonary barotrauma
Sutures
Sinus barotrauma