The lesser saphenous vein is a venous blood vessel that runs up the length of the leg. It originates from the junction formed between two small veins in the foot, the fifth toe’s dorsal vein and the dorsal venous arch.

This vein is smaller in size than the great saphenous vein, which is the dominant superficial blood vessel of the calf and thigh. The dorsal venous arch serves as the bridge between the saphenous veins.

The lesser saphenous vein is considered the second major superficial blood vessel in the leg. The vein travels the length of the ankle near the malleolus (the bony protrusion on each side of the ankle) and continues up the back of the calf. It is extended alongside a nerve in the leg called the sural nerve. The lesser saphenous vein then merges with the popliteal vein located near the knee joint.

The saphenous vessel lies right below the skin. The lesser saphenous vein may suffer from thrombophlebitis, a condition in which a blood clot prompts a vein to swell. Lesser saphenous thrombophlebitis can cause pain and inflammation of the extremities. The application of warm compresses along with a drug therapy regimen is recommended for treatment.