What are varicose veins?

Veins are thin-walled blood vessels that carry blood from the body tissues back to the heart. Varicose veins are blood vessels close to the surface of the skin that have enlarged and twisted due to failure of the valves within the veins. Blood collects and pools in sections of the vein, causing the vein to bulge and swell. The veins are visible and can be felt as ropy structures under the skin. Although varicose veins usually occur in the legs and feet, they can occur on any part of the body.

Varicose veins may result in some discomfort and in some cases can cause serious medical problems. For some people, varicose veins only cause a problem in terms of appearance where they choose not to wear shorts or skirts that may show their legs.

There are two vein systems in the body:

Deep veins: These are not visible through the skin and are deep adjacent to the muscles. These carry about 90 percent of the blood.

Surface (superficial): These are veins which are often visible just beneath the skin. Surface veins do not have the protective muscular surrounding that the deep veins do; therefore, they are weaker and more likely to become varicose. Surface veins carry blood from the skin and surface areas to the deep veins through connecting channels called perforator veins.

Pathway of blood to the heart:

  • The leg muscles squeeze the deep veins, forcing the blood upward.
  • The veins have one way valves to prevent the blood from flowing backwards.
  • As the blood is pushed upward, the valves open to allow the blood to pass.
  • After each heartbeat, the valves close momentarily to prevent backward-flow.

Valve failure results in the following:

  • Blood flowing the wrong way
  • Deep veins may pump blood into surface (superficial) veins
  • Increases pressure in surface (superficial) veins
  • Surface veins swell from excess blood and increased pressure resulting in varicose veins

Why valves fail:

  • There may be too few valves
  • The valve may be shaped incorrectly
  • The vein walls may be weak
  • The valves may be damaged by blood clots
  • Increase of pressure on the veins caused from:
    • Obesity
    • Pregnancy
    • Prolonged standing