Deep leg veins (the light blue veins in the picture) include the
iliac, femoral, popliteal, and tibial veins. Superficial leg veins (the dark
blue veins) include the greater and lesser saphenous veins.
In deep vein thrombosis, a blood clot (thrombus) forms in a deep
vein, usually in the legs. Clots also can form in superficial veins, which are
closer to the skin.
