[Differentiation of human and nonhuman primate ribs]

The ribs of 9 human beings and 6 animal-primates (4 Pongidae and 2 Cercopithecidae of 2 different species) had been examined metrically with regard to their relative dimensions and proportions. Special care was taken as well of the differentiation of single ribs of one individual as of interspecific differentiation. Generally the Pongidae show the greatest relative-dimensions. This concerns both the diameter as the length. The individuals of the genus Homo have medium-sized dimensions, while the Cercopithecidae have the smallest. In this way a first grouping of the measurements becomes possible. As for the rib-diameter Homo concurs more with the Pongidae than with the Cercopithecidae. At first from the rib-proportions resulted an indication to special similarity between the Pongidae and recent man from whom the Cercopithecidae distinctively differ as it is shown by the indices angulus-sternal end/tuberculum-angulus. A divariate presentation of the measurements of this index, however, proves that Homo concerning the single measurements occupies an intermediate position between the Pongidae and the Cercopithecidae in this case, too (Fig. 5). The examination of the craniocaudal trend of different ribmeasurements (length, depth and area of the rib-arc) produced a special similarity of the 4 upper ribs between the Pongidae and Homo. In the region of the lower chest a great conformity between the Pongidae and the Cercopithecidae became obvious in this respect. A different trend shows up in Homo - probably as an expression of the transformation-process in the human chest. The intraspecific morphometric discrimination of the single ribs proves to be especially difficult, above all between the 7th to 10th rib, if the ribs of an individual are not completely present. It is, however, possible in some cases by means of some measurements and indices of these ribs.