The aim of this study was to provide morphometric data, obtained from macerated mandibles, which might facilitate the topographic location of the mandibular foramen, considering aspects such as gender, age and ethnicity. One hundred and eighty-five macerated mandibles of adult black and white individuals of both sexes were analyzed. Initially, 5 points were established: MF, the lowest point of the mandibular foramen; S, greatest concavity of the mandibular notch; A, anterior margin of the ramus of mandible; P, posterior margin of the ramus of mandible; and Go, gonion. Then the following measurements were performed bilaterally: MF-S, MF-A, MF-P and MF-Go. The following mean values were found: MF-S: 21.02 mm for white females (WF) and 22.00 mm for black females (BF); 24.40 mm for white males (WM) and 24.35 mm for black males (BM); MF-A: 17.05 mm for WF and 18.09 mm for BF; 17.18 mm for WM and 18.11 mm for BM; MF-P: 11.11 mm for WF and 12.24 mm for BF; 13.10 mm for WM and 14.15 mm for BM; MF-Go: 19.00 mm for WF and 19.44 mm for BF; 23.13 mm for WM and 22.12 mm for BM. The values found in this study, considering gender, age and ethnic group, can be used as a parameter to carry out the sagittal split ramus osteotomy technique, making it more predictable and with less risk of complications.