Whereas arteries bring blood to the extremities and organs, veins are vessels that return the blood to the heart. The human body has surface (superficial) veins that are connected to deep veins by bridging (perforator) veins. Unlike arteries, which have thick muscular walls designed to withstand higher pressures, veins have thin, less muscular walls and are prone to dilate in response to persistently increased pressures. The calf muscles act as pumps to keep blood flowing through the legs back to the heart. Veins have delicate valves that keep blood flowing toward the heart and prevent backflow of blood into the legs.
What Are Varicose Veins?
Varicose veins are superficial veins that have become abnormally enlarged and cause symptoms or are cosmetically distressing. Types of varicose veins include spider veins, which are reddish-bluish and thread-like; reticular veins, which are bluish and string-like; and true varicose veins, which are large rope- or worm-like veins that feel spongy to the touch and bulge out from the skin surface (Figure).