What does the duplex ultrasound show?
When your legs are dependent, there is often no blood flow in the veins in your legs. Blood moves in the veins when the calf muscle is squeezed and therefore compresses the vein and moves the blood. After the blood moves forward, there are a series of one-way valves which close, thereby preventing the backwards flow of blood. When the valves fail, there is added blood flow and pressure in the veins leading to varicose veins.