Background: In forensic medicine, sexually dimorphic bones such as pelvic bones like the os sacrum, greater sciatic notch parameter, and sacral dimensions are typically used to determine a person's sex. Before complex autopsy preparations are made, a postmortem CT scan offers a quick and simple way to illustrate and measure bone structures.

Aim: To emphasize role of pelvic bone measurements in sex determination, to estimate sex using based on morphometric data from computed tomography images of sacrum and greater sciatic notch and to develop a regression equation formula for estimating the sex from the most accurate measurements.

Methods: This cross-sectional study was conducted in Tripoli Medical Center, Center for Judicial Expertise and research, Libya and Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Zagazig University. Subjects were divided into group I: included 65 male and group II: included 65 female. All participiants were subjected to Pelvic CT scan examinations.

Results: CT measurements of the sacral vertebra (m.t.d, a.p.d, area and perimeter except m.s.d) were significantly higher in males compared to females, while all CT measurements of the greater sciatic notch were significantly higher in females compared to males. The area of the sacral vertebra and the the width of the greater sciatic notch were the only significant variable in sex determination.

Conclusion: CT scan was a valuable method in measuring the selected pelvic sacral dimensions. The estimated values of pelvic measurements by using 3D CT images could develop a pelvic model with a regression formula with high accuracy value.