Recent case reports implicate pneumatic antishock garment (PASG) usage in subsequent development of compartment syndromes. The anterior tibial compartment pressures of eight healthy volunteers were selected for study at varying PASG inflation pressures. A wick catheter method provided continual intramuscular compartment pressure (IMP) monitoring throughout the period of study. A linear correlation between PASG pressure and IMP exists, with more than 90% of the externally applied pressure being transmitted to the muscle compartment. All subjects developed IMP greater than 50 mm Hg at PASG inflation of 60 mm Hg. Externally applied pressure appears to create a condition that may stimulate or lead to a compartment syndrome. Inflation pressure should be monitored closely during PASG application, because IMP can be assumed to be at least as high as inflation pressure. The lowest effective PASG pressure should be used.