The saphenous veins are part of the network of superficial veins of the foot and leg. These superficial veins interconnect to form a complex network below the skin and drain into two major trunks: the small and great saphenous veins. The small saphenous vein begins on the lateral portion of the foot and passes upward, rising along the back of the calf, enters the popliteal fossa (a depression in themycontentbreak bone behind the knee) to join the popliteal vein. The great saphenous vein, which is the longest vein in the body, begins on the medial side of the foot. It rises along the inner side of the leg and penetrates deep into the thigh just below the inguinal ligament in the lower abdomen, where it joins the femoral vein. Near its upper end, it receives vessels that drain the upper thigh, groin, and lower abdominal wall. The femoral and the great saphenous veins merge into the external iliac vein.