Keywords
forensic anthropology, occipital morphology, sex estimation, ontogenetic changes
Abstract
Sex estimation is vital to building the biological profile in forensic anthropology. Cranial nonmetric traits are often used in adult sex estimation due to their sexually dimorphic nature. However, only one nonmetric trait is assessed on the occipital despite the bone’s postmortem durability. While these sex estimation methods were developed for use on adult crania, juvenile sex estimation is less accurate due to differences in the age at which individuals reach sexual maturity. The aim of this study was to improve upon existing sex estimation methods by accounting for shape differences that exist within the occipital. This study used computed tomography (CT) scans from the New Mexico Decedent Image Database consisting of 127 males and 124 females between birth and 25 years. Surface models of the CT scans were generated and three-dimensional coordinates (5 landmarks and 45 curve semilandmarks) were used to evaluate occipital morphology. A generalized Procrustes analysis, principal component analysis (PCA), and discriminant function analysis were applied to the scans to identify shape changes in the occipital. Nonmetric traits assessed on the surface models included nuchal crest, bun, torus, and median nuchal line. Chi-squared and Fisher’s exact tests were used to identify if significant differences existed between sexes for each nonmetric trait. The PCA results show no sexual dimorphism in occipital shape. After identifying when nonmetric traits appear dimorphic via frequency data, chi-squared and Fisher’s exact tests revealed sexual dimorphism in the nuchal crest and median nuchal line, which is in line with previous studies on sexual dimorphism in the nuchal region. The data suggests that the nuchal crest could be used in sex estimations as early as 15 years, indicating it may be useful for sex estimation in adolescents. However, the absence of dimorphism in occipital shape prevents this element from being considered as a sex indicator.
Completion Date
2024
Semester
Fall
Committee Chair
Schultz, John
Degree
Master of Arts (M.A.)
College
College of Sciences
Department
Anthropology
Format
Identifier
DP0029047
Language
English
Release Date
December 2024
Access Status
Dissertation/Thesis
Campus Location
Orlando (Main) Campus
STARS Citation
Barritt, Jennifer S., "Evaluating Sexual Dimorphism in Occipital Morphological Shape Through Modern Human Ontogenetic Changes" (2024). Graduate Thesis and Dissertation post-2024. 8.
https://stars.library.ucf.edu/etd2024/8
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