Morphometric Analysis of the Human Mastoid Process and its Application in Forensic Sex Determination Within a Nigerian Cohort

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 437–448

DOI: 10.46882/2026/IJAP/000204

Article Type: Original Research Article

Title: Morphometric Analysis of the Human Mastoid Process and its Application in Forensic Sex Determination Within a Nigerian Cohort

Names of Authors: Chijioke U. Okafor¹, Ngozi O. Achebe²

Authors’ Affiliations: ¹Department of Anatomy, Faculty of Basic Medical Sciences, University of Medical Sciences, Ondo, Nigeria; ²Department of Human Anatomy, College of Health Sciences, Nnamdi Azikiwe University, Nnewi, Nigeria

Abstract:
The skull remains one of the most reliable skeletal structures for anthropological sex determination, with the petrous and mastoid regions demonstrating high resistance to taphonomic damage. This study quantified the morphometric features of the human mastoid process to establish baseline discriminant functions for sex classification within a Nigerian population. Linear dimensions were measured on 90 dry adult crania (55 males, 35 females) of known sex obtained from anatomical archives. Parameters evaluated included mastoid length, mastoid breadth, anteroposterior diameter, and the calculated mastoid triangle area. All linear measurements were performed bilaterally using a digital vernier caliper. The mean mastoid length was significantly greater in males than in females (28.45 ± 2.12 mm vs 22.15 ± 1.84 mm, p < 0.001). The calculated mastoid triangle area yielded a mean value of 782.4 ± 45.2 mm² for males and 612.8 ± 38.5 mm² for females, demonstrating substantial sexual dimorphism (p < 0.01). Discriminant function analysis revealed that compounding mastoid length and triangle area provided an overall predictive accuracy of 82.4% for correctly assigning sex. No statistically significant side asymmetry was observed within either group (p > 0.05). These quantitative standards confirm that the mastoid process exhibits marked structural dimorphism, offering a robust tool for physical anthropologists and forensic experts in regional skeletal identification workflows.

Keywords: Mastoid Process, Morphometry, Anthropometry, Forensic Science, Sex Determination, Cranium

Manuscript Timeline: Received: August 21, 2026; Revised: September 16, 2026; Accepted: September 26, 2026; Published: September 30, 2026

Citation: Okafor C.U., & Achebe N.O. (2026). Morphometric Analysis of the Human Mastoid Process and its Application in Forensic Sex Determination Within a Nigerian Cohort. International Journal of Anatomy and Physiology, 15(9), 437–448. DOI: 10.46882/2026/IJAP/000204

Subscribe to read the full article: https://www.internationalscholarsjournals.org/subscribe-to-read