The lesser saphenous vein, also called the small saphenous vein, is a superficial vein that runs along the posterior (back) aspect of the calf from the ankle up to the popliteal fossa behind the knee, where it typically drains into the popliteal vein. It is an important structure evaluated during venous duplex ultrasound when assessing for deep vein thrombosis or venous insufficiency. Reflux in the lesser saphenous vein, meaning backward flow of blood due to faulty valves, can contribute to varicose veins and chronic venous symptoms in the leg. Sonographers assess this vessel for compressibility, flow direction, and the presence of clot.
Sonography Term