Arteries carry blood from the heart to the rest of the body. Arterial blood flows under high pressure with fast flow. Veins carry blood from the end points of the body back to the heart under low pressure with slow flow. There are two main divisions of the venous system: the superficial and deep venous systems. The perforating or communicating veins connect the superficial and deep venous systems. Veins have thin valves in them that keep blood flowing upward. When closed, the valves prevent the blood from backing down the leg by the pull of gravity. The valves open with exercise and inhaling and close when not moving the legs or exhaling.

Venous Conditions

The most common types of venous disease involving the legs are:

Patients can experience mild symptoms such as burning or cramping over varicose veins, or a heavy feeling in the legs from chronic venous insufficiency. They may also develop "thrombus" or clotting in one or more veins termed deep vein thrombosis when involving the veins within the limbs and superficial thrombophlebitis when involving one of the superficial veins. Ultrasound testing is performed to determine the presence or absence of venous thrombosis, thrombophlebitis, and chronic venous insufficiency.