Increased lower-leg intracompartmental pressure compromising neuromuscular function within that compartment is termed compartment syndrome. This condition may be acute (often trauma induced) or chronic (usually exercise related). In a conscious, alert patient, acute compartment syndromes usually are easy to diagnose clinically; however, in the unconscious patient, a diagnostic aid such as the intracompartmental pressure monitor is useful. Using the slit catheter device, compartmental pressures in excess of 30-35 mmHg in a normally perfused patient suggest the need for open compartment fasciotomy. Chronic compartment syndromes require dynamic pressure measurements for an accurate diagnosis. The most important parameters are elevated postexercise pressures and delayed restoration of normal compartmental pressures. Subcutaneous fasciotomy may be sufficient in accurately diagnosed cases of chronic compartment syndrome.