Abstract
To better understand the abnormal venous system, we need to first understand the
normal lower extremity venous system. There are basically two venous systems that
coexist and interconnect in the legs. The deep system consists of single or duplicate
veins that accompany the major arterial system throughout the extremity. In the
thigh, a companion vein accompanies the common, deep, and superficial femoral
as well as the popliteal arteries. Below the popliteal space, the veins continue to
accompany the major tibial and peroneal arteries down into the foot but are usually
duplicate or even triplicate. The deep system by definition runs in the deep spaces in
the leg and is contained within compartments surrounded by dense, non-compliant
fascia. The superficial system, in contrast, runs within the softer fatty subcutaneous
tissue and has a much less regular anatomy. The greater saphenous vein which runs
medially down the leg beginning at the groin, and the lesser saphenous vein which
runs laterally down the calf beginning in the popliteal space are the largest and most
anatomically predictable of these veins. They join the deep system draining into the
common femoral vein in the groin at the sapheno-femoral junction and into the
popliteal vein in the popliteal space at the lesser saphenous-popliteal junction,
respectively. The deep and superficial systems are also connected along the medial
and, to a lesser extent, lateral aspects of the calf by the so-called perforating veins
which pass through perforations in the fascia. These are multiple and are located
at relatively predictable anatomic locations particularly along the lower half of the
medial calf.