Diagnóstico de sexo y edad en la caja torácica mediante análisis óseo y de imágenes 3D

Abstract

Introduction: Sex and age estimation are essential for the reconstruction of the osteobiological profile in Forensic Anthropology. In this aspect, the rib cage has been the subject of different studies in this field in different populations. However, given that, on numerous occasions, bone remains are very damaged and fragmented, it is necessary to develop specific methodologies for the estimation of sex and age in bone fragments. However, the wide human variability makes it necessary for the different methods developed to be validated in other populations. Material: For the present work, bones from adult individuals taken from four identified osteological collections have been studied: the San José Osteological Collection (Granada) and the Lucena Collection (Córdoba), both deposited in the Anthropology Laboratory of the University of Granada; the Skeletal Collection of Coimbra and the 21st Century Skeletal Collection, both deposited in the Dept. of Life Sciences of the University of Coimbra. In addition, a series of 3D thoracic images of adult individuals, belonging to the 3D Image Collection held by the Anthropology Laboratory of the University of Granada, on loan from the Castilla-La Mancha Health Service, have also been studied. Methods: First, a metric study of the neck of the first to fourth ribs of the Granada Collection was carried out to develop discriminant functions for the sex estimation in a Spanish population. Subsequently, these discriminant functions have been tested in the Lucena Collection to check their usefulness. Secondly, in order to check their usefulness in sex estimation in the Portuguese population, the discriminant functions have been tested in the two Portuguese collections referenced. Thirdly, the usefulness of sternal segment synostosis for age estimation has been tested in the Granada Collection. Finally, using the 3D Image Collection, different metric variables have been studied for the development of discriminant functions for sex estimation, as well as the ossification of the different thoracic cartilages to check their correlation with age, and thus develop regression formulae for age estimation. Results: The obtained results have shown the existence of sexual dimorphism in the neck of the first to fourth ribs in the Spanish population, presenting significant differences between both sexes. This has allowed the construction of a set of discriminant functions, which allow the estimation of sex with up to 93,2% accuracy, a percentage that rises to 96,4% in the validation of the functions in the Lucena Collection. With respect to the validation in the different Portuguese collections, large discrepancies were found when applying the results in the CISC Collection, where the results indicate that there are large differences in the first and second ribs with the Granada Collection. On the other hand, when applying the functions in the Portuguese 21st Century Collection, the results are more positive, allowing sex estimation with up to 93% accuracy. On the other hand, the synostosis of the sternal segments in relation to age estimation did not yield significant results, presenting very high age ranges, not allowing an accurate estimation. On the other hand, with regard to sex estimation using 3D images, the results showed significant differences between sexes in the variables analysed, allowing the design of univariate and multivariate discriminant functions, with which sex estimation was achieved with up to 85,1% accuracy in the univariate functions and 89,6% in the multivariate functions. Finally, with respect to age estimation using 3D images, the degree of ossification of the different costal cartilages showed a good correlation with the real age of the individuals, thus enabling the design of predictive models for age estimation, used for the development of regression formulae that allow age estimation with good results. Conclusions: In conclusion, the results suggest: 1) the usefulness of rib necks for sex estimation in the Spanish population using discriminant functions; 2) the utility of these functions for sex estimation in Portuguese populations; 3) the ineffectiveness of the study of sternal synostosis for age estimation in adults; 4) the value of 3D image analysis for sex estimation using discriminant formulas; and 5) the potential of the study of thoracic cartilage ossification using 3D images for age estimation.