What Causes Varicose Veins?

Saphenous vein incompetence is the underlying cause in about 90% of patients with severe varicose veins.

Each leg has two saphenous veins;

1. Great saphenous vein (GSV)
   The GSV runs up from the ankle along the inside of the calf and thigh and drains into the main deep vein in the groin.

2. Small saphenous vein (SSV)
   The SSV is half the length and much shorter and runs up from the outside of the ankle along the back of the calf and drains into the deep vein behind the knee.

So close to 90% of patients with severe varicose veins require closure (ablation) of one or both saphenous veins.

There are at least eight other patterns of varicose veins and in total they make up about 10% of all other types of varicose veins.