Which statement regarding compartment syndrome is correct?

• A. Most cases of compartment syndrome occur following a severe fracture of the pelvis.
• B. In most cases, compartment syndrome develops within a few minutes after an injury.
• C. Compartment syndrome occurs because of increased pressure within the bone cavity.
• D. Compartment syndrome typically develops within 6 to 12 hours after an injury.

Answer: (D)

Compartment syndrome happens when pressure within a closed muscle compartment rises enough to cut off blood flow and damage tissues. After an injury, swelling and bleeding inside the compartment gradually increase the pressure, so the problem usually develops over hours rather than instantly. The typical window is about 6 to 12 hours after the injury, which is why that timing statement is the best answer. It’s not most common after a pelvis fracture—anatomic sites more prone to this condition are the limbs, especially fractures of long bones like the tibia or forearm, or crush injuries. The issue is pressure within the muscular-fascial space, not pressure inside a bone cavity. Onset within minutes would be unusually quick; swelling needs time to build. Early signs include severe pain out of proportion to exam and pain with passive movement, with firm, swollen compartments; if untreated, it can lead to nerve damage, muscle necrosis, and other serious complications, necessitating urgent fasciotomy.