Proširene vene

Proširene vene su pre svega uzrokovane uspravnim stavom čoveka kao vrste, čemu se venski zalisci nisu uspeli evolucijski prilagoditi. Uloga zalistaka kod zdravih pojedinaca jeste da usmeravaju vensku krv prema srcu a da sprečavaju povratni tok krvi u venama, međutim kod obolelih pojedinaca zalisci počinju da popuštaju i postaju nefunkcionalni, što uzrokuje nedovoljni dotok venske krvi prema srcu, izaziva povratni tok i zadržavanje krvi u venama, koje tada počinju da se šire. Varicose veins are primarily caused by the vertical position of man as a species, to which the vein valves fail evolutionarily adapted. The role of the valve in healthy individuals is to drive venous blood to the heart and to prevent backflow of blood in the veins, but in diseased individuals valves begin to subside and become non-functional, causing insufficient flow of venous blood to the heart, causing backflow and retention of blood in the veins that were beginning to spread.