Intracompartmental pressures were measured by the wick catheter technique in sixty-five compartments of twenty-seven patients who were clinically suspected of having acute compartment syndromes. A pressure of thirty millimeters of mercury or more was used as an indication for decompressive fasciotomy. The range of normal pressure was from zero to eight millimeters of mercury. Eleven of these patients were diagnosed as actually having compartment syndromes and in these patients, twenty-seven compartments were decompressed. Only two patients had significant sequelae. In the sixteen patients (thirty-eight compartments) whose pressures remained less than thirty millimeters of mercury, fasciotomy was withheld and compartment syndrome sequelae did not develop in any patient. Intraoperatively the wick catheter was used continuously in eight patients to document the effectiveness of decompression. Fasciotomy consistently restored pressures to normal except in the buttock and deltoid compartments, where epimysiotomy was required to supplement the fasciotomy. Continuous intraoperative monitoring of pressure by the wick catheter technique allowed us to select the few cases in which primary closure of wounds was appropriate and to decide which patients were best treated with secondary closure.