Which sign best indicates acute compartment syndrome of the forearm?

• A. Severe pain out of proportion to exam and pain with passive stretch, often with tense swelling.
• B. Mild pain relieved by rest
• C. Numbness without pain
• D. Diminished pulse

Answer: (A)

Recognizing acute forearm compartment syndrome centers on a sign that shows early muscle ischemia from rising intracompartmental pressure: severe pain that is out of proportion to the exam and worsened by passive stretching of the muscles in the area, often with tense swelling. This combination is the most sensitive early clue because the pressurized compartment irritates nerves and muscles, causing intense pain that cannot be explained by external findings alone. Pulses may still be present early, so a diminished pulse is a late finding and not reliable for early diagnosis. Numbness can occur as ischemia progresses, but pain—especially with passive stretch—is the hallmark. Mild pain relieved by rest does not fit acute compartment syndrome, since the underlying pressure issue would typically persist or worsen with activity. When suspicion is high, urgent management is required to prevent muscle necrosis and nerve injury.