Changes have occurred in the original concepts which led to the current use, either totally or partially, of the various cephalometric tests, and the terminology employed varies from one author to another. A comparative study of the principal measurements used was therefore conducted, based on this acquired knowledge. After discussing the relative values of the reference points and constructions, the authors attempt to establish a relationship between the different evaluation methods used for each element, bony, alveolar, and dental, which are necessary for diagnosis, and for which functional coexistence dominates the prognosis for harmony of the buccodental system.