Destruction or incompetence of individual venous valves need not necessarily have clinical consequences. On the other hand, it may result in a “chain reaction” by causing an increase of pressure in the distal portion of the vein, which may lead to dilation and, thereby, incompetence of the valve located at the next site upstream (see p. 23). The specific clinical significance of individual venous valves varies. We may assume that the destruction of an individual valve — e. g. by thrombosis of its pocket — need not have clinical consequences if there are still healthy valves proximal to it. A key position is held by those valves whose location is centralmost since they are not protected by other valves at sites proximal to theirs. The valves separating the deep leg veins from the superficial leg veins are also in a key position as severe differences of pressure occur at their sites. In contrast to the superficial veins, the deep veins are protected by surrounding striated muscles so that they are only rarely subjected to unphysiologic dilation. A key position of particular significance is held by the valves at the entrances of the long and short saphenous veins into the deep leg veins. The valves located at these sites are obviously subjected to particular strain, especially in the absence of more proximal competent valves. The entrances ofthe long and short saphenous veins may also be regarded the largest perforating veins.
KeywordsSaphenous Vein Varicose Vein Superficial Vein Spermatic Vein Venous Valve
Unable to display preview. Download preview PDF.