On a continuous series of 1000 lower limbs, the Author correlates the by Leriche and Fontaine described stages in arterial occlusive disease of lower limbs, with parameters given by a set of functional vasculary tests: Doppler, tetrapolar rheography, digital plethysmography, transcutaneous measure of PO2 (Tc PO2). The ankle systolic pressure index is a good method to value the importance of arterial occlusion, but it reflects not so well the clinical severity of ischemia. The degradation of the digital plethysmography pulsated signal and of the Tc PO2, is proportional to the ischemia degree with a very good specificity in stages III and IV. The reography indexes, the quantification of leg arteries (Doppler), the digital plethysmography, show that the major opposition between stage II and stage III - IV is the quality of peripheral vascular bed. It appears that the notion of leg arteries outflow must be completed with a notion of compensation in distally and of global peripheral vascular bed (leg arteries--arteriolary system--microcirculation). The set of the used methods allows only to retain two different groups: the first one gathering asymptomatic or responsible of an effort ischemia lesions (corresponding to stage I and II), the other gathering responsible of permanent ischemia, which impends gangrene (corresponding to stages III and IV). In the presence of rest pain or trophic disorder, the joined data of digital plethysmography and of Tc PO2, are more discriminating than the single impression and allow to discover some false stages III and IV.