Femoral artery narrowing. Coloured angiogram (blood vessel X-ray) of the femoral artery (red) in the upper leg, showing narrowing at centre right. The femur (thigh bone, brown) is seen down left. Narrowing (stenosis) is usually caused by the deposition of plaques of atheroma (a fatty substance) on the inner walls of arteries in atherosclerosis. Such narrowing can reduce the blood flow to the parts of the body supplied by the artery. In the legs, it may cause claudication (pain on walking that is relieved by rest). Risk factors for atherosclerosis include a high-cholesterol diet, smoking, high blood pressure and obesity.