A varicose vein is one that is so dilated that the valves do not close to prevent backward flow of blood. Such veins lose their elasticity,become elongated and tortuous,and fibrous tissue replaces the tunica media.
PREDISPOSING FACTORS.
- Heredity- there appears to be a familial tendency.
- Gender- females are affected more than males .
- Pregnancy.
- Age- the progressive loss of elasticity in vein walls that accompanies increasing age leads to less efficient elastic recoil.
- Reduced efficiency of the skeletal muscle pump,as in prolonged standing/sitting,or obesity,where excess adipose tissue around veins does not give adequate support.
- Pressure- because of their thin walls,veins are easily compressed by surrounding structures,leading to increased venous pressure distal to the site of compression.
VARICOSE VEINS OF THE LEGS.
When valves in anastomong veins between deep and superficial leg veins become incompetent,the venous pressure in the superficial veins rises. In the long term they stretch and become chronically dilated because the superficial veins are less well supported by surrounding tissues than deeper ones. Such areas show through the skin as varicose veins.
The skin over a varicose vein may become poorly nourished due to stasis of blood,leading to the formation of varicose ulcers,usually on the medical aspects of the leg just above the ankle.
