The Use of Near Infrared Spectroscopy in the Diagnosis of Acute Compartment Syndrome

This is a prospective observational study to determine the reliability and accuracy of Near Infrared Spectroscopy (NIRS) to detect oxygen flow in the extremities of injured and non-injured soldiers over time. This technology may be useful in the detection of acute compartment syndrome. We hypothesize that: * NIRS values will be well-correlated with intracompartmental pressure measurements * NIRS values will be significantly different between non-injured and injured extremities, and injured extremities treated with fasciotomy for acute compartment syndrome. * NIRS values of the upper extremity and feet will correlate to values from normal legs in critical control patients and patients with unilateral sever lower extremity injuries.