There are usually one or more bunches of enlarged and tortuous veins in the region of the knee. Frequently a large branch establishes a communication between the systems of the great and small saphenous veins in the region of the popliteal space, or across the front of the upper part of the tibia. The superficial position of this last branch and its proximity to the bone render it liable to injury.
Fig. 67.—Extensive Varix of Internal Saphena System on Left Leg, of many years' standing.
The small veins of the skin of the ankle and foot often show as fine blue streaks arranged in a stellate or arborescent manner, especially in women who have borne children.
Complications.—When the varix is of long standing, the skin in the lower part of the leg sometimes assumes a mahogany-brown or bluish hue, as a result of the deposit of blood pigment in the tissues, and this is frequently a precursor of ulceration.
Chronic dermatitis (varicose eczema) is often met with in the lower part of the leg, and is due to interference with the nutrition of the skin. The incompetence of the valves allows the pressure in the varicose veins to equal that in the arterioles, so that the capillary circulation is impeded. From the same cause the blood in the deep veins is enabled to enter the superficial veins, where the backward pressure is so great that the blood flows down again, and so a vicious circle is established. The blood therefore loses more and more of its oxygen, and so fails to nourish the tissues.
The ulcer of the leg associated with varicose veins has already been described.
Hæmorrhage may take place from a varicose vein as a result of a wound or of ulceration of its wall. Increased intra-venous pressure produced by severe muscular strain may determine rupture of a vein exposed in the floor of an ulcer. If the limb is dependent, the incompetency of the valves permits of rapid and copious bleeding, which may prove fatal, particularly if the patient is intoxicated when the rupture takes place and no means are taken to arrest the hæmorrhage. The bleeding may be arrested at once by elevating the limb, or by applying pressure directly over the bleeding point.
Phlebitis and thrombosis are common sequelæ of varix, and may prove dangerous, either by spreading into the large venous trunks or by giving rise to emboli. The larger the varix the greater is the tendency for a thrombus to spread upwards and to involve the deep veins. Thrombi usually originate in venous cysts or pouches, and at acute bends on the vessel, especially when these are situated in the vicinity of the knee, and are subjected to repeated injuries—for example in riding. Phleboliths sometimes form in such pouches, and may be recognised in a radiogram. In a certain proportion of cases, especially in elderly people, the occurrence of thrombosis leads to cure of the condition by the thrombus becoming organised and obliterating the vein.