Aneurysmal varicose veins (Latin variculus + Greek aneuryzis - absence of blood), also known as systolic varicose veins, systole aneurysm or systole-dependent dysfunction, is an enlargement of a thinned section of the wall of the great saphenous vein below the knee, caused by pulsating blood flow from the peripheral veins during systole. This symptom is a consequence of overload of the venous wall and a violation of its ability to stretch. The source of this syndrome is overstrain of the valve apparatus of the great saphenous and deep veins, which experience pressure in the knee area due to excessive stress on the legs. Frequency