Anatomy of the venous system in the limbs
Arterial blood flows through the main axial arteries to the upper and lower limbs. It returns via the deep and superficial veins. In the upper limb the superficial veins are more important in carrying blood back to the heart. In the lower limb, the superficial veins carry only about 10 per cent of the blood, while the remainder passes via the deep veins. The superficial veins lie superficial to the muscle fascia of the limb. The principal superficial veins in the leg are the long and short saphenous veins. In the arm, the cephalic and basilic veins are the principal superficial veins.
Interestingly, venous diseases occur much more frequently in the lower limb than in the upper limb, and most often in the superficial veins. The deep veins of the lower limb may be the site of life-threatening venous thrombosis or venous valvular incompetence resulting in leg ulceration. Each major axial artery has at least one and often a pair of accompanying veins named after the artery. The superficial and deep veins join at a number of points. The short saphenous vein terminates at the saphenopopliteal junction (SPJ) and the long saphenous vein at the saphenofemoral junction (SFJ) in the groin. Here the flow in the superficial veins joins that in the deep veins. There is, in addition, a number of places in the calf and thigh where flow in the superficial veins may also join that in the deep veins. These is the ankle, calf and thigh communicating or perforating veins. The names of these veins come from their course from the superficial to the deep venous system in which they perforate the deep fascia of the leg. Near the ankle are the Cockett perforating veins, near the knee the Boyd perforators and in the thigh the Hunterian perforating vein. All veins in the upper and lower limbs contain valves every few centimetres which ensure that blood flows towards the heart.
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