The veins of the body include deep veins and superficial veins. Deep veins travel deeper and are generally located in the deeper layers of the muscle. Superficial veins are superficial and are usually located in the superficial fascial layer. The deep veins collect the blood supply to the deep muscles and tendons. The superficial veins collect the subcutaneous blood supply. The superficial veins usually travel for a period of time and then inject into the deep veins. In clinical practice, the veins are mainly blocked or dilated, but when the deep veins are dilated, the clinical symptoms are not very obvious. When the superficial veins are dilated, they are more likely to be manifested as varicose veins in the lower extremities. When the deep vein is blocked, it causes significant swelling of the limb and deep vein thrombosis, while the symptoms of superficial vein thrombosis are not obvious.