What is the hallmark symptom of decompression sickness?

The hallmark symptom of decompression sickness, often referred to as "the bends," is joint and muscle pain. This pain is typically described as a deep, aching sensation and is commonly located in the large joints, such as the shoulders, elbows, knees, or ankles. The pain arises from nitrogen bubbles forming in the tissues and joints due to the rapid decrease in pressure experienced during an ascent after a dive.

When divers are exposed to high-pressure environments, nitrogen from breathing gases dissolves into their blood and tissues. If a diver ascends too quickly, the reduction in pressure can cause this dissolved nitrogen to come out of solution, forming bubbles. These bubbles can cause irritation and elicit pain in the joints and muscles, which is a significant and classic manifestation of decompression sickness. Identifying this symptom is crucial for early diagnosis and treatment, as it can lead to more severe complications if not addressed promptly.