The red rectangular boxes are the essential scanning sites and planes for the femoral arteries and the popliteal artery. The numbers within the boxes represent the general steps of scanning. The schema in the box demonstrates the typical US features of arteries and veins at each scanning site. GSV, greater saphenous vein; FV, femoral vein; CFA, common femoral artery; SFA, superficial femoral artery; DFA, deep femoral artery; SSV, small saphenous vein; POPV, popliteal vein; POPA, popliteal artery
