The Veins Of The Leg
The venous Pump
In the human, the return of venous blood from the lower limbs to the heart requires the assistance of a pump equipped with non return valves, as the force generated by the heart alone cannot overcome the forces of gravity to drive the blood from the toes to the brain. The pumping action in the deep veins is provided by the muscles. Their contractions, acting within the strict confines of the encircling deep facia, squeeze the blood, at high pressure, towards the heart. On the journey to the heart, the blood also travels through the long and the short saphenous veins in the superficial system embedded in the fatty tissue surrounding the muscles and therefore at much lower pressure. The muscle fascia partitions the two systems with Perforator Veins linking the two through the facia. Provided the venous valves are working efficiently and the muscle is pumping effectively, the return of the blood to the heart is assured.
Vulnerability to varicose veins is one of the prices paid by mankind for walking upright. By standing, the pressure to which the venous valves are subjected can be very high; particularly for those guarding the communications between the superficial and deep vein systems at the Perforator Veins. Should these valves fail, blood from the deep vein system is ejected at high pressure into the low pressure superficial valves creating venous hypertension. This vein becomes congested and dilates resulting in the twisted, swollen appearance of a varicose vein close to the surface of the skin.
Failure of any of the venous valves can occur for a number of reasons, but tend to be familial. Often first appearance is in the early months of pregnancy when increased oestrogen levels and blood volume can cause the vein walls to relax and become enlarged. The normal pressures of being upright can be exacerbated by being overweight and or involved in occupations that may involve standing for long periods e.g. shop assistants, air stewardesses, nurses. Valves may also be damaged by trauma - sport, domestic and work environments can all create potential for a blow to weaken valves in the superficial system. Early symptoms of varicose veins may include tired aching legs, leading into cramping pains in the limb, with itching or "tingling" sensations on the surface.
Varicose veins can be a progressive condition - one incompetent valve will put pressure on the next and create further damage leading in a minority of instances to Chronic Venous Insufficiency (C.V.I.) as a result of this continued and worsening venous hypertension. This can in turn lead to inflammation and eczema and ultimately for a small percentage, venous ulcers of the leg.
Venous Leg Ulcers
Although associated with varicose veins, venous leg ulcers can develop from damage within the deep vein system, such as Deep Vein Thrombosis (DVT). The veins become irreparably damaged resulting in venous insufficiency characterised by stasis of the blood and oxygen starvation in the tissues.(1) One of the most common causes of DVT is the post-thrombotic state after childbirth.
Other factors are:
- surgical operations
- injury to the leg
- prolonged bed rest
A leg suffering from venous insufficiency is liable to ulceration, often after a minor injury, or continued scratching of the skin of a leg which has been rendered eczematous by C.V.I.
The primary aim of conservative treatment is the control of venous hypertension and associated oedema by restoration of the venous pump.
By using graduated compression therapy the roll of the calf muscle is enhanced allowing the venous pump to work more efficiently. Increased tissue pressure and consequent decreased venous diameter accelerates blood velocity. The blood is then assisted in travelling towards the heart, helping to reduce stasis(2)(3)
While graduated compression hosiery will not cure varicose veins, it will provide relief from the symptoms and help prevent further damage or complications such as C.V.I.
Venous Leg Ulcers
Compression therapy can help to improve the flow of blood and is recommended during venous ulcer treatment and to prevent a recurrence.
A number of studies(4)(5) have shown that graduated compression hosiery has a significant role to play in reducing incidence of leg ulcer recurrence when used as part of a preventative programme.
- Dale J. J. The prevalence and treatments of lower leg ulcers in the Community, Lothian Health Board 19 79.
- Struckman J. Mathiesen FR. Low compression high gradient stockings in patients with venous insufficiency.. Effect on the muscular venous pump, plethysmographic results. American College of Surgeons Chicago 1985.
- Christopolous D. C et al. Airlplethysmography and the affect of elastic compression on venous haemodynamics of the leg. Society of Vascular Surgery, New Orleans 1986.
- Moffatt CJ Dorman MC, Recurrence of leg ulcers within a community ulcer service JWC 1995 4..9, 5 7-6.
- Cherry G W, Leg ulcers; in support of stockings. Comm. Outlook 1986,-8.-29-31.
Article LinksSee other medical related articles:
- About Futuro: Support Hosiery
- About Mediven Compression Stockings
- About T.E.D. Anti-embolism Stockings
- Compression Classes for Graduated Compression Hosiery
- Prevention of Deep Vein Thrombosis (DVT)
- Skin Breakdown and TED Stockings
- Taking good care of your legs
- TED Stockings: Proven DVT reduction through published peer reviewed clinical studies
- Tips and Tricks for Healthy Legs
- Veins of the Leg
- When a blood clot forms in the leg ... (.jpg, 119Kb) The Sunday Times, 30 December 2001
- CE Marking (European Medical Device Directive 93/42/CEE)