Valves in Veins: An Historical Survey

Abstract

The history of the knowledge of valves in veins is traced from the sixteenth century, when they were first described, to the present day. Valves are of two kinds, ostial and parietal; the former are inserted into part of the circumference of a tributary vein-entry, the latter rise from the vein-wall. The number of cusps in a single valve may be from one to five, but the most frequent form, at all events in man, is the bicuspid. Canano was probably the first to mention venous valves, and Alberti was the first to publish drawings of them. Fabricius gave the earliest detailed account of their distribution in the body, but failed to grasp their physiological significance. William Harvey saw more clearly than Fabricius, and was led by his deductions to the discovery of the circulation. Since his time much work has been done on the distribution of valves in man, and, to a smaller extent, in the lower animals. This work, in its beginnings qualitative, has in later times become more and more quantitative, and the relation of valves to age, sex, and other variable factors has been, at all events partially, investigated. The development of the valves in fœtal life has been studied, and has produced most important findings. With the progress in anatomical knowledge has come more certainty as to the physiology. The function of valves is to give irreversibility of direction to the bloodstream in the veins; they are not anti-gravity mechanisms, nor are they directly concerned with varicosis. In the higher animals they occur chiefly in the veins of the limbs, and are relatively deficient in the large veins of the abdomen and thorax. In co-operation with the muscular movements they effect the return of blood from the extremities to the centre of the body. Here the absence of valves makes the large veins into a venous cistern, whose capacity can be varied by contraction of the abdominal muscles and the movements of respiration. The supply of blood to the right heart can therefore be adjusted to the requirements of the organisms. © 1927, The Royal Society of Medicine. All rights reserved.