On standing, the crural veins are subject to increased hydrostatic pressures impairing their function as a blood vessel and blood depot. In addition to hemodynamic changes there are shifts in the balance between capillary filtration and reabsorption in the sense of an increase in interstitial fluid volume up to the development of a visible edema. These effects may be compensated partly through the function of the so-called muscle vein pump and by venoconstrictive reactions. Insufficient compensation will entail disorders of cell supply which may lead to chronic venous insufficiency. In addition to clinical investigation methods the bi-directional ultrasonic measurement of flow velocity based on the Doppler principle is relatively simple and suitable for the functional diagnosis of superficial veins. Therapy may be initiated by physicotherapeutic, pharmacotherapeutic and surgical measures.