Fluid dynamics and venous hemodynamics in the lower extremities.

Chronic venous disease is a vascular disorder characterized by impaired venous return and a progressive dysfunction of the venous system. Pathological reflux can occur due to abnormal dilation and weakening of the vein wall. The circulatory system is a natural structure in which physical laws, such as the law of closed containers and gravity, operate. The malfunctions in the system also adhere to these laws of nature. This article explains how the principles of fluid dynamics apply to the flow of blood in the veins of the legs. I am discussing the principles of Pascal's law, Torricelli's law, Bernoulli's law, and Poiseuille's law, and how they are relating to the anatomy and physiology of the venous system.