Acute compartment syndrome (ACS) of the lower extremity is a clinical condition that is seen fairly regularly in modern orthopedic practices. Although the pathophysiology of the disorder is well known to physicians who care for patients with musculoskeletal injuries, the diagnosis is often difficult to make. A delay in diagnosis that leads to a delay in treatment can result in permanent disability. Delayed or missed diagnosis can be devastating to both patients and members of the health care team.