Investigating the sex-related geometric variation of the human cranium
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Accurate sexing methods are of great importance in forensic anthropology since sex assessment is among the principal tasks when examining human skeletal remains. The present study explores a novel approach in assessing the most accurate metric traits of the human cranium for sex estimation based on 80 ectocranial landmarks from 176 modern individuals of known age and sex from the Athens Collection. The purpose of the study is to identify those distance and angle measurements that can be most effectively used in sex assessment. Three-dimensional landmark coordinates were digitized with a Microscribe 3DX and analyzed in GNU Octave. An iterative linear discriminant analysis of all possible combinations of landmarks was performed for each unique set of the 3160 distances and 246,480 angles. Cross-validated correct classification as well as multivariate DFA on top performing variables reported 13 craniometric distances with over 85% classification accuracy, 7 angles over 78%, as well as certain multivariate combinations yielding over 95%. Linear regression of these variables with the centroid size was used to assess their relation to the size of the cranium. In contrast to the use of generalized procrustes analysis (GPA) and principal component analysis (PCA), which constitute the common analytical work flow for such data, our method, although computational intensive, produced easily applicable discriminant functions of high accuracy, while at the same time explored the maximum of cranial variability.
KeywordsGeometric morphometrics Cranial metric traits Discriminant functions Greek population
The authors would like to thank the two anonymous reviewers for their comments, which not only improved the quality of the present paper but also helped us further explore certain aspects of our work resulting in improved classification results. The present study and the use of the Athens Collection have been approved by the Department of Animal and Human Physiology. Preliminary results of this study have been communicated (Oral Presentation) at the 3rd Iberian Symposium on Geometric Morphometrics in Girona, Spain. The present study did not receive any funding.
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Conflict of interest
The authors declare that they have no conflict of interest.
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