We know that the arterial system of the body is responsible for carrying oxygen-rich blood to tissues and organs throughout the body, while the venous system is responsible for carrying blood back to the heart. The saphenous vein is a superficial vein located in the inner part of the lower extremity, from the foot to the root of the thigh and then to the deep veins in the lower extremity. A large amount of blood in the lower extremity is returned mainly through the deep veins, and the saphenous vein is responsible for only a small portion of this, so the deep veins of the lower extremity are the most important return veins of the lower extremity. There is a communication vein between the deep veins of the lower extremity and the saphenous vein. There is also a small saphenous vein on the lateral side of the lower leg, which joins the popliteal vein at the back of the knee. Normally, when we stand, the blood in the vein flows downward under the force of gravity, which is contrary to the way venous blood should return to the heart. Thankfully, there is a single opening valve within our veins, medically known as a venous valve. So how do the venous valves manage to send blood from the veins back to the heart? When the muscles in our lower extremities contract, the muscles squeeze the deep veins that run through them and blood will flow back toward the heart, when the valve is open. And when the muscles relax, the pressure above the valve is higher than below the valve and the blood will flow backwards. At this point, the valve closes and blood cannot flow back below the valve. This action of the muscles is medically called “muscle pump action”, and it is by this muscle pump action that blood from the lower extremities flows back to the heart. In addition, our heart beats and breathing also have an important role in promoting blood flow back. When we walk or exercise, the muscles of the lower extremities contract and stretch regularly, through this muscle pump action, blood will flow back to the heart along the veins. And when we stand still or sit still for a long time, the blood flow back to the veins of the lower limbs will slow down or even stagnate, and the pressure in the veins will increase. Generally, our veins can tolerate and regulate this pressure increase, but if the vein wall is weak, or if the elasticity of the vein wall is congenitally poorly developed, or if some objective factors are acquired, it will make it difficult for the veins to withstand this pressure, resulting in dilatation of the veins, thinning of the vein wall, destruction of the vein valves, and the veins being stretched and becoming tortuous, which eventually leads to the disease of saphenous varicose veins. This is the reason why professions that work on their feet for long periods of time (e.g. teachers, salesmen, surgeons) are prone to this disease. From the above, we can understand that saphenous varicose veins are mainly due to various reasons that lead to unhealthy and weak vein walls, which become tortuous and dilated under prolonged venous pressure and appear on the legs as curved, worm-like protrusions above the skin surface. These varicose veins are more visible when standing and disappear when lying down, because of the reason that “water flows downhill”. Since the saphenous vein is unhealthy, the valves in the vein have been damaged, when standing the venous blood of the lower limbs will stagnate in the vein, making the vein under greater pressure, while lying down the blood in the vein flows back to the heart, so naturally the varicose veins cannot be seen. This varicose veins will become heavier over time, and the long-term blood stagnation will cause malnutrition in the skin of the lower limbs, which may result in brown patches of skin, blackening, skin pigmentation, and even ulcers, ulcers, and long lasting healing. The stagnant blood in the varicose blood vessels may also form thrombosis, forming phlebitis and even leading to deep vein thrombosis in the lower limbs.