Which part of the ear is primarily affected during descent while scuba diving?

The middle ear is primarily affected during descent while scuba diving due to the changes in ambient pressure. As a diver descends, the pressure around them increases, but the air in the middle ear does not automatically equalize with the increasing external pressure. This can lead to discomfort or pain, often resulting in a condition known as barotrauma if not properly managed.

The Eustachian tube connects the middle ear to the throat and allows for pressure equalization. Divers need to perform techniques like Valsalva or Frenzel maneuvers to help facilitate this equalization and avoid injury. The inner ear and outer ear canal, while important for hearing and balance, are not primarily affected during the pressure changes of a descent. The inner ear is involved in balance and hearing but is more susceptible to issues during rapid changes or ascents, rather than descent.