Eight patients with an anterior thigh muscle contusion or rupture developed an acute anterior compartment syndrome. All patients had an increased pressure in the quadriceps muscle, ranging between 41 and 80 mm Hg. At fasciotomy, three cases had a hematoma in the rectus femoris and four in the vastus intermedius, and in one case only, edema of the anterior compartment was found. Postoperatively, there was immediate pain relief in all cases, and after about 4 weeks, all patients had normal function. We recommend broad indications for fasciotomy and evacuation of hematoma after thigh muscle contusion or rupture.