Venous Anatomy

To better understand how vein disorders occur, are treated and can be prevented, it is first important to know how veins function in your body and their purpose.

Blood flows through a system of blood vessels, also known as veins and arteries.  Arteries carry oxygen-rich blood from the heart to the rest of the body.  Veins are the blood vessels responsible for transporting blood back towards the heart, from the organs and limbs.  

Veins contain a series of one-way valves which move the blood through the vein, helping along the way to fight the force of gravity.  The valves function like curved doors, opening to let the blood flow towards the heart, and then closing to hold it in place, preventing any backward flow.  The valves are spaced at intervals along the inside wall of the vein.  

When the valves are healthy (competent), they close tightly.   When they are not healthy (incompetent), they do not close completely and blood can then flow backward, pool inside the vein and cause the vein to dilate, meaning it swells or expands abnormally.  This can lead to painful and sometimes serious medical conditions commonly known as venous disease.  Some examples of venous disease are spider veins, varicose veins, venous stasis disease and thrombophlebitis.