Venous thrombosis is the result of occlusive clot formation in the veins. It occurs mainly in the deep veins of the leg (deep vein thrombosis, DVT), from which parts of the clot frequently embolize to the lungs (pulmonary embolism, PE). Fewer than 5% of all venous thromboses occur at other sites (see "Thrombosis at Rare Sites," and "Superficial Thrombophlebitis," below). Venous thrombosis is common and often occurs spontaneously, but it also frequently accompanies medical and surgical conditions, both in the community and the hospital. The symptoms of venous thrombosis are nonspecific, and therefore the clinical diagnosis is difficult and.
