A varicose vein is a permanent dilation of a superficial vein. This dilation prevents the return of blood to the heart. Dilated superficial veins take on a bluish color. Varicose veins usually appear on the legs, but they can also appear on the thighs.

The diagnosis of varicose veins is made after a physical examination since the varicose vein is easily recognizable. Various clinical tests can be performed to assess the significance of venous insufficiency. This test can be confirmed by a venous Doppler ultrasound that reveals blood flow and circulation. They also sometimes allow finding causes that can be treated. A phlebography or x-ray of the venous system may also be performed.