Which of the following describes air trapped under the skin, usually around the neck?

Air trapped under the skin, especially around the neck, is referred to as subcutaneous emphysema. This condition occurs when air leaks into the subcutaneous tissue, usually as a result of an injury, trauma, or certain medical procedures. The presence of air in this layer of skin can cause a characteristic swelling and a crackling sensation when touched, often described as "rice crispy" like.

Subcutaneous emphysema may sometimes accompany other conditions, but it specifically points to the air being beneath the skin as opposed to within the lung cavities or blood vessels, which would characterize other conditions like pneumothorax or mediastinal emphysema. Understanding this distinction is vital for diagnosing and treating the condition appropriately, particularly during medical evaluations related to scuba diving incidents where barotrauma may occur.