Veins are blood vessels that return deoxygenated blood from the outer parts of the body back to the heart and lungs. When veins become abnormally thick, full of twists and turns, or enlarged, they are called varicose veins. Generally, the veins in the legs and thighs have a tendency to become varicosed.
 

• The thickened, twisting or dilated parts of the vein are called varicosities.
  
   
• Varicose veins can form anywhere in the body, but they are most often located in the legs.
  
   
• In the United States alone, about 19% of men and 36% of women have varicose veins.
  
   
• Varicose veins tend to be inherited and become more prominent as the person ages.

Veins in the leg are either superficial or deep.
 

• The superficial veins and their branches are close to the skin. These veins typically become varicosed. Also included in this category are the communicator or perforator veins, which connect the superficial veins with the deep veins.
  
   
• The deep veins are encased by muscle and connective tissue, which help to pump the blood in the veins and back to the heart. The veins have one-way valves to prevent them from developing varicosities.
  
   
• Generally, blood travels from the superficial veins to the deep veins. From there, the blood travels through a network of larger veins back to the heart.

Varicose Vein Causes

Many theories exist for why varicosities occur in veins, but the consensus is that defective/damaged valves within the veins are to blame.

Valves prevent backward flow of blood within the vein. They keep blood in the vein moving toward the heart. Why the valves stop working is up for debate.

• Some experts think inherited problems cause some people to have too few valves or valves that do not function properly.
  
   
• Some people may be born with abnormalities of the vein wall. The resulting weakness may predispose the valves to separate and become leaky.

The result is that when a person with poorly functioning valves stands up, the blood flow actually reverses and flows down the superficial veins, when it should be flowing up, toward the heart.
 

• When the muscles surrounding the deep veins contract, emptying the deeper veins, a build-up of pressure occurs.
  
   
• This causes even more blood to go the wrong way from the deep to the superficial veins through faulty valves in the perforator veins.
  
   
• This increases pressure in the superficial veins and causes varicosities.

Many factors can aggravate the situation.
 

• Pregnancy is associated with an increase in blood volume. Also, added pressure on the veins in the legs by the weight of the growing uterus and the relaxation effects of the hormones estrogen and progesterone on the vein walls contribute to the development of varicose veins during pregnancy.
  
   
• Prolonged standing
  
   
• Obesity or distended belly
  
   
• Straining: Chronic constipation, urinary retention from an enlarged prostate, chronic cough, or any other conditions that cause you to strain for prolonged periods of time causes an increase in the forces transmitted to the leg veins and may result in varicose veins. These mechanisms also contribute to the formation of hemorrhoids, which are varicosities located in the rectal and anal area.
  
   
• Prior surgery or trauma to the leg: These conditions interrupt the normal blood flow channels.
  
   
• Age: Generally, most elderly individuals show some degree of varicose vein occurrence.