In a patient with a high a priori risk of peripheral vascular disease, the positive predictive value of an abnormal physical diagnostic examination is high. In patients with a low prior probability of peripheral vascular disease, the physical examination makes little contribution to the diagnosis or exclusion of arterial insufficiency. For this purpose the ankle-brachial systolic pressure index is preferable. Peripheral arterial disease is unlikely when this index is normal. However, a low ankle-brachial index necessitates further investigations to determine possible arterial insufficiency in the lower extremities.