The natural history of pelvic veins

The paired leg and pelvic veins as well as the gonadal and renal veins flow into the unpaired inferior vena cava. The abdominal aorta splits into two iliac branches. This results in numerous crossings of the closely adjacent vessels and causes hemodynamic effects. The reason behind this lies in the embryological development. Early on in human development, primitive arteries and veins form from a capillary network. The limb, renal and testicular veins as well as the inferior vena cava develop from the cardinal vein system and are initially created in pairs. Remodelling and regression processes in the cardinal venous system during embryonic development explain the special anatomy of the retroperitoneal veins as well as the pathophysiological conditions underlying the various forms of PeVD.