Which skull features are commonly used for sex estimation, and how reliable are they relative to pelvic features?

• A. Pelvic features are more reliable than skull features; skull features can provide moderate accuracy
• B. Mastoid process size, nuchal crest, and supraorbital margins; accuracy moderate and less reliable than pelvic features
• C. Cranial sutures size and orientation determine sex
• D. Long bone robusticity predicts sex better than pelvis

Answer: (B)

The key idea is that skull traits can inform sex estimation, but they don’t reach the reliability of pelvic indicators. Among the skull features used, the size of the mastoid process, the prominence of the nuchal crest, and the characteristics of the supraorbital margins are the ones most often relied on. The mastoid process tends to be larger and more robust in males; the nuchal crest is usually more pronounced where neck muscles attach, also showing a male-leaning pattern; and the supraorbital margins tend to be thicker and more rugged in males and smoother in females. When these traits are evaluated together, they can yield a moderate level of accuracy for sex assessment from skull remains.

However, skull-based estimates are less reliable than pelvic-based estimates. The pelvis exhibits stronger and more consistent sexual dimorphism across populations, so pelvic features—such as the subpubic angle, greater sciatic notch, and other pelvic dimensions—generally provide higher accuracy. Population variation, age, and preservation can further affect skull trait reliability, whereas pelvic traits tend to remain more discernible for sexing when the pelvis is available.