[Variations of the right bile ducts. The futility of complete anatomical classifications].

Combination calculus shows that there is a considerable number of theoretical variations of the right ducts: [table: see text] Complete classification is therefore impossible, and the different frequencies of these variations in different series are easy to understand. Probably some of these theoretical distributions do not actually exist. A classification should be limited to a description of the mechanisms of variation (duplication and sliding on other ducts), to a list of the most frequent variations; dangerous distributions from the surgical point of view, even if they are exceptional, must be pointed out. Interesting conclusions can be reached when there is a significant difference between a theoretical and a practical frequencies. For the surgeon, an excellent cholangiography (in three dimensions if possible) is the key of his strategy. Direct approach of the vasculo-biliary sheaths is the key of a speedy and safe surgery: in a sheath the surgeon finds only the branches supplying the parenchyma entered by this sheath.