Leg thrombosis is called lower extremity arteriovenous thrombosis in medical terminology. Lower extremity arteriovenous thrombosis includes two conditions: lower extremity arterial thrombosis and lower extremity venous thrombosis, and the symptoms of both types of thrombosis have their own characteristics. Lower extremity arterial thrombosis: arteries are the blood vessels that transport blood and oxygen to the body, and arterial thrombosis blocks the arteries and mainly causes ischemic symptoms in the legs. Pain, pale skin color and reduced skin temperature, weakening or disappearance of arterial pulsation, impairment of leg sensation and movement may occur in the legs, and intermittent claudication and limb color change, or even ulceration may occur over time. If the embolism is prolonged, localized limb necrosis may result, and even amputation may be necessary. Deep vein thrombosis of lower limb: Vein is the blood vessel for returning blood, after the vein thrombosis blocks the vein, it mainly causes the obstruction of blood return to the leg, and due to the blood stagnation in the leg, the patient’s leg will have edema and swelling, as well as superficial vein dilatation and local skin temperature increase. It can also cause local ulcers in the lower limbs and even infection and necrosis. In serious cases, such as local arterial compression, it can cause local ischemia and even necessitate amputation. Besides judging leg thrombosis from symptomatic manifestations, further examinations such as ultrasonography, arteriography, and lower limb venous cascade angiography are needed to clarify the cause and lesion location and to formulate a treatment plan. In summary, the symptoms of leg thrombosis depend on what blood vessels are involved, and arterial thrombosis behaves differently from venous thrombosis.