venous valve

A fold in the venous endothelium to prevent a backflow of blood. Venous return from the extremities, especially the legs, must flow against the effects of gravity. The venous valves ensure a one-way flow & protect against venous stasis. Varicose veins may occur when the venous valves become damaged or non functional.

References

Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999.