Anatomy and physiology of the lower-extremity deep and superficial veins.

A thorough understanding of venous anatomy and physiology is foundational to the diagnosis and management of venous disease. Compared with the arterial system, there is significantly greater developmental variation in the venous system. The veins of the lower extremity include the superficial and deep veins, which are defined by their respective relationships to the muscular fascia. Perforating veins traverse the muscular fascia to connect superficial and deep veins. Communicating veins connect veins within the same venous compartment, either deep to deep or superficial to superficial. The deep veins of the lower extremities primarily drain muscles and are encompassed by muscular fascia. The veins located between the skin and the muscular fascia are considered superficial veins. Superficial veins drain the cutaneous microcirculation. The pelvic venous system is a complex transitional outflow pathway between the lower extremities, the pelvic structures, and the inferior vena cava. The terminology used to describe lower-extremity, pelvic, and abdominal vasculature conforms to published international standards.