Sex estimation using the second cervical vertebra: a morphometric analysis in a documented Portuguese skeletal sample

Abstract

Biological sex estimation is one of the main parameters required in the construction of a biological profile of an unknown deceased person. In corpses in an advanced state of decomposition, skeletonized or severely mutilated, bone analysis may provide the only way to access biological sex. Although the hip bones are the most dimorphic and useful bones for sex estimation, they are often badly preserved and/or fragmented or may not even be present in some cases. For that reason, it is necessary to develop sex estimation methods based on bones less dimorphic. In this study, 13 dimensions of the second cervical vertebra were measured in order to quantify sex-related variation and to generate a simple predictive model based on logistic regression analysis. For logistic regression fitting, 190 individuals from the Coimbra Identified Skeletal Collection were used as a training sample. The resulting model was also evaluated in an independent test sample composed of 47 individuals from the Identified Skeletal Collection of the 21st Century (University of Coimbra). The developed logistic regression model correctly estimated known sex in 86.7 to 89.7 % of the cases. The second cervical vertebra demonstrated to be a useful alternative for sex estimation when other skeletal elements are not available or suitable for analysis. This method seems promising but more reliability studies are required for a more robust validation.

A method for sex estimation using the proximal femur

“…The LR models are slightly biased towards the correct estimation of sex in males, a pattern commonly reported in other studies [8,15,31,32,34] -although not always [9].…”

“…As suggested by other researchers [34][35][36], sex-specific accuracy possibly relates with secular change in bone dimensions, usually associated with a higher misclassification of females when employing a method fitted in a chronologically older sample that has, in comparison, been affected by a positive secular trend. FNAL, at least, is known to display secular change in both sexes, with a more pronounced increase in women [37].…”

Identification of sex and age for Egyptians using computed tomography of the first lumbar vertebra

“…Many authors were able to identify sex from measurements taken from the second cervical vertebra at accuracy rates ranged from 70% to 92.9% (Bethard and Seet, 2013;Gama et al, 2015;Torimitsu et al, 2016;Wescott, 2000). Moreover they proved that the second cervical vertebra is a good sex identifier especially when bigger bones are damaged.…”

Morphological and functional implications of sexual dimorphism in the human skeletal thorax

“…Sexual dimorphism has been observed as an important source of intraspecific variation in living and fossil hominins (Frayer & Wolpoff, ). In current day human populations, it has been addressed both at cranio‐facial (Bastir, Godoy, & Rosas, ; Bulygina, Mitteroecker, & Aiello, ; Hall, ; Lam, Pearson, & Smith, ; Loth & Henneberg, ; Rosas & Bastir, ; Rosas et al, ; Steyn & Işcan, ; Wood, Li, & Willoughby, ) and postcranial levels (Arsuaga & Carretero, ; Bastir, Higuero, Ríos, & García Martínez, ; Carlson, Grine, & Pearson, ; Gama, Navega, & Cunha, ; Işcan & Shihai, ; Kranioti & Michalodimitrakis, ; Navega, Vicente, Vieira, Ross, & Cunha, ; Reno, Meindl, McCollum, & Lovejoy, ; Richmond & Jungers, ; Rodriguez‐Perez, ; Rosas et al, ; Rosas et al, ; Ruff, ) with size and shape differences between males and females. It is important to note that some of these shape changes could be explained by allometry (shape differences explained by differences in size), since males are generally larger than females.…”