What may occur if a diver blows long and forcefully against a pinched nose while struggling to equalize ears?

Blowing forcefully against a pinched nose while attempting to equalize ear pressure can lead to a range of physical injuries due to the pressure exerted within the ear structures. The correct answer relates to the potential risk of round window rupture, which can occur when excessive pressure is applied to the inner ear.

The round window is a membrane-covered opening that serves as a pressure release valve in the inner ear. When a diver exerts prolonged and forceful pressure while trying to equalize, this can exceed the tolerance of the round window membrane, leading to a rupture. This injury can result in a number of symptoms, such as hearing loss and balance issues, as the integrity of the inner ear is compromised.

Understanding this risk emphasizes the importance of proper equalization techniques and the need to avoid excessive force during equalization attempts. Proper training and awareness of the body's limits are crucial for safe diving practices.