A 32-year-old woman complains of pain and swelling in her left leg. Symptoms have been worsening over the past couple of days. On examination of her leg, the physician notes a palpable cord that travels medially from the area of the knee to the groin. Ultrasound does not show any evidence of deep venous thrombosis. What is the most likely diagnosis? Chronic venous insufficiency. Acute arterial occlusion. Superficial thrombophlebitis. Compartment syndrome. Atherosclerosis obliterans.