 Perforator veins play a very special role in the venous system , carrying blood from superficial to deep veins . During the muscular <unk> their valves close and stop any blood flow coming from the deep to the superficial veins . When their valves become insufficient , they are responsible for a rapid deterioration in existing varicose disease and for the development of venous ulcers . Detection of insufficient perforators is important because they need to be <unk> . However , the detection of competent ones is as important because they may be used strategically in new techniques of conservative surgery , for example a minimally invasive CHIVA . The ultrasonography report will include insufficient and continent perforators , which will also be shown on venous mapping . To test these veins properly , the examiner will need to use some techniques like the Paraná maneuver , toe and foot flexion , and hyper @-@ extension on tip toes . 
