3 types of veins

• Superficial veins collect the blood just beneath the skin.

• Perforating veins carry blood from the superficial veins to the deep veins.

• Deep veins run through the muscles and carry 90% of the blood back to your heart.

Anatomy of a vein

Veins have cup-like flaps called valves spaced along their inside walls. Valves open upward, so blood can move up the vein. Valves close to keep blood from falling back down the vein.