Accessory saphenous vein
The accessory saphenous vein is linked to the greater saphenous vein, which runs parallel to it, and is located in the leg and thigh. The greater saphenous vein is a large superficial vein that originates where the foot's dorsal venous arch merges with the large toe's dorsal vein. It travels up the leg's medial side after passing anteriorly to the medial malleolus. The accessory saphenous vein joins it just before it drains into the femoral vein. When the accessory saphenous vein reaches the knee, it travels posteriorly along its medial aspect, along the thigh's medial aspect, and finally across the posterior border of the femur bone's medial epicondyle. The accessory saphenous vein then travels medially across to the thigh's anterior surface before entering the saphenous opening of the fascia lata, known as the saphenous hiatus. It attaches to the femoral vein in the saphenofemoral junction of the femoral triangle. The greater accessory saphenous vein branches out into smaller accessory saphenous veins made of elastic fiber. These have diminished muscle cells and thin walls. They are often the cause of varicose veins, which develop when they dilate.
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In Depth: Accessory saphenous vein