21. Venogram — proximal thigh

The superficial and deep veins of the lower limb also communicate via perforating vessels, whose valves allow blood to flow from the superficial to the deep system. While a superficial vein on the dorsum of the foot was injected to perform this study, it is predominantly the deep veins which are visualized filled with contrast because a turniquet around the ankle prevented significant filling of the superficial system.