Lower extremity venous thrombosis may cause swelling, pain and necrosis of the limb. 1. Swelling of limbs: when the lower extremity veins are blocked by thrombus, it will often lead to the obstacle of blood return in the veins, and then there will be localized bruising leading to swelling of limbs, and craters will appear when pressed by hand. 2. Limb pain: venous thrombosis of the lower limbs will affect the peripheral nerve tissues, due to the obstruction of blood supply to the nerve tissues, the pain of the affected limb may occur and will continue to worsen. 3. Limb necrosis: if the lower extremity venous thrombosis is blocked for a long time, the local limbs will be in the state of long-term ischemia and hypoxia, and necrosis or wet gangrene may occur. These are some common symptoms of lower extremity venous thrombosis. Patients with lower extremity venous thrombosis should follow the doctor’s instructions for regular checkups and treatment.