What Are the Different Veins of the Leg?

Lower extremity veins refer to the blood vessels of the lower limbs of the human body, which are divided into two groups, deep and shallow, and communication veins between deep and superficial veins. Superficial veins eventually merge into deep veins. The physiological function of human venous blood vessels is to ensure that venous blood flows from the distance to the center.

Lower limb vein

Lower extremity veins refer to the blood vessels of the lower limbs of the human body, which are divided into two groups, deep and shallow, and communication veins between deep and superficial veins. Superficial veins eventually merge into deep veins. The physiological function of human venous blood vessels is to ensure that venous blood flows from the distance to the center.

Lower limb muscle contraction is an important condition that promotes venous blood flow to the heart. During contraction, the venous valve opens, and the perforating branch vein valve closes, pushing the blood to the heart. When the muscles relax, the venous valve has the opposite phenomenon, and the superficial vein blood flows to the deep vein. Therefore, the force of blood return when muscles contract, while normal valves are a condition for blood return. Therefore, the veins of the lower limbs are also called "second heart".

Chinese name

Lower limb vein

Classification

Deep and shallow

Nature

Blood vessel

Attribution

Soft tissue

The deep veins of the lower limbs are accompanied by the artery of the same name, and the deep veins of the lower leg, that is, the anterior tibial, posterior tibial, and peroneal veins, are paired, and accompany the two sides of the artery of the same name. It is a superficial femoral vein, which merges with the deep femoral vein at the groin (root of the thigh) into the common femoral vein, and then continues upward to the external iliac vein.

The superficial veins of the lower limbs include the great saphenous vein and

There are many valves in the deep, superficial veins, and communication veins. The valves are generally located on the distal side of the main branch of the vein, and its function is to ensure unidirectional return of venous blood.

The number and location of deep vein valves in the lower limbs vary from person to person. The general rule is that at the distal end of the venous branch, more valves are present. The most constant valves are located in the deep femoral vein and the superficial femoral vein before the meeting, each with a pair of valves; the second pair of superficial femoral vein valves are mostly located about 10 cm below the first pair of valves; the common femoral vein is mostly a pair, located in the femur Proximal heart of common vein; popliteal vein has 2 more pairs of valves. The number of valves in other veins is large and not constant.

The venous valve is formed by venous intimal folds, and most of them have two corresponding and symmetrical leaflets, that is, double valve type. Each leaflet has a free edge and an attachment edge. In the double-valve type, the junction of the free edge and the attachment edge is the meeting point of the two leaflets. Most of the venous swelling near the valve attachment margin is the sinus. Through in vitro mechanical tests, the pair of superficial femoral veins has the strongest pair of valves, which can withstand reverse pressure of 350-420mmHg. In the superficial venous system, the saphenous femoral vein valve (the pair of valves before the great saphenous vein merges into the common femoral vein) is the strongest, but only 180-250 mmHg, and the valves below it become weaker. Under normal circumstances, when the blood returns to the heart, the valve is attached to the vein wall, and the vein is unobstructed. When venous pressure increases due to standing or other reasons, under the impact of reverse blood flow, the two leaflets open and the free edge closes to prevent blood from flowing backward. At this time, the sinuses were swollen and shaped like bamboo sticks.

The venous valve of the lower limb is different from the heart valve, and its activity is affected by many factors. The venous return of venous blood in the lower limbs, in addition to the effects of inhalation of the thoracic cavity and negative pressure suction during diastole, mainly rely on the squeezing effect of the calf muscle pump and the one-way opening function of the venous valve, so that the blood It flows from the distal end to the proximal end and from the superficial vein to the deep vein. The one-way opening function of the valve is of great significance. It effectively prevents the backflow of blood when the calf muscles relax. It ensures the blood return when the human body is upright.