What is venous reflux?

Vein Valve Collapse. Veins contain one way valves which under pressure can sometimes fail and allow blood to backflow or "reflux". This is what leads to spider or varicose veins.
Leaking Vein Valves. The job of veins is to circulate blood back to the heart. To work properly the veins need valves inside them to prevent blood from flowing backwards, eg towards the feet when standing. Venous reflux is when the blood flows backwards seen on a doppler ultrasound and can lead to symptoms such as aching, and fatigue and conditions like varicose, spider veins, leg swelling and even leg sores.
Malfunctioning valve. Veins in many areas of the body have microscopic, thin one way valves. These valves together with the muscle contraction of the calves propel the blood up the leg. If these valves malfunction due to age, clot, trauma, hereditary or pregnancy, then the blood will leak backwards causing reflux. Reflux can result in not only varicose and spider veins but also venous stasis and venous insufficiency.
Valve failure. The veins transport blood back to the heart. Extremity veins have numerous one way valves which allow blood to flow in one direction, toward the heard. When these valves fail, blood is allowed to flow back flow or "reflux". Pooling of blood or stagnated blood results in varicose veins. Superficial vein pressure is one of the causes for spider or varicose veins.

Related Questions

What causes jugular venous reflux?

Physiology. The jugular vein connects directly to the superior vena cava and then to the right atrium of the heart. When the heart is overfilled, the jugular vein becomes distended. If you press on the liver, you can accentuate this ("hepato-jugular reflux") and that observation is used to increase the sensitivity of the physical exam for early signs of heart failure. Read more...
Heart failure. Mostly fluid overload on the right side of the heart leading to jugular venous dissension and reflex. Read more...