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Sex determination using mastoid process length in dry skulls of Nigerian population

MOJ Anatomy & Physiology
Chinna Nneka Orish, Hakeem B Fawehinmi

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Introduction: Identification of an individual is very crucial in any medicolegal investigation. Age, sex and stature are the primary factors that help in the identification. Skull is important in this regard as it resists adverse environmental conditions over time. The present study aims to determine sexual dimorphism of mastoid length in Nigerian skulls.

Material and methods: One hundred adult dry skulls, (78 males, and 22 females) free from damage and deformities collected from eleven Departments of Anatomy in Nigerian Universities were used. Automatic digital caliper was used to measure mastoid length. Data was analyzed with Graph Pad Prism 5.03. The mean, coefficient of variation, correlation, linear regression, percentiles, sexual dimorphism ratio were computed. 

Results: The left mastoid length (mm) of male and female skulls were 34.27±0.49 and 30.41±0.32mm respectively while the mean of right mastoid length (mm) of male and female were 35.48±0.37 and 31.25±0.36mm respectively. Male parameter was significantly higher than female atp<0.5. Correlation of craniometric parameters of Nigerian male/female population showed left female mastoid length versus right had no correlation {Y=0.02x+30.65(0.017)} and the fit line was straight while male mastoid length left versus right had positive significant correlation{Y=0.67x+12.62(0.59*) and the fit line sloped upward.

Conclusion: The result of this study will be of importance in providing new perspectives on human osteology and in sex determination in forensic anthropology.


skull, sex determination, anthropometry, mastoid length, physical anthropology, bilateral parameters, linear regression, sexual dimorphism, female crania, mastoid length, racial variations, human skulls, racial differences, sexual dimorphism ratio, anthropometric parameters