The clinical features of arterial insufficiency in the lower limb are reflected by the relative needs of various tissues for oxygen and nourishment. Exercising muscle, being the most active metabolic tissue in a limb, registers its relative anoxia by stimulating pain receptors. This pain is brought on by exercise and relieved by rest. As the degree of ischaemia increases, the claudication distance becomes shorter until the patient suffers from continuous pain at rest. Progressive arterial insufficiency eventually leads to deterioration in skin nutrition with ulceration. The death of skin and deeper structures in the foot and leg is followed by infection and gangrene.