Determination of sex of sacrum in adult Macaca mulatta1

[Abstract] Background Sacrum being a part of pelvis is an important bone for identification of sex in both living primates and fossil ones. Aim Aim: of this work was to examine the sex differences of sacral parameters in rhesus macaques and to compare with those of the other primates. Materials and Methods Fifty-six adult scara of macaques (17 males and 39 females) have been investigated. Measurement of various parameters was done using sliding vernier calliper; and statistical analysis was done using SPSS 23.0 package. Results The present study showed that the cranial breadth of the sacrum, the sacral length, transverse diameter and sagittal diameter of the cranial articular surface, and two indices of relative sacral breadth were highly significant for sex determination in Macaca mulatta . Comparison of the present data with other studies suggest that sex determination of sacrum can be very different in various types of primates. Conclusion The results suggest that these measures may be functionally integrated in response to locomotion, obstetric adequacy and cephalopelvic proportions in primates. Sacral index is more reliable and should be applied for sex determination of sacrum in various anatomical and anthropological investigations.