Inmaculada Alemán Aguilera

Image analysis of pubic bone for age estimation in a computed tomography sample

Radiology has demonstrated great utility for age estimation, but most of the studies are based on metrical and morphological methods in order to perform an identification profile. A simple image analysis-based method is presented, aimed to correlate the bony tissue ultrastructure with several variables obtained from the grey-level histogram (GLH) of computed tomography (CT) sagittal sections of the pubic symphysis surface and the pubic body, and relating them with age. The CT sample consisted of 169 hospital Digital Imaging and Communications in Medicine (DICOM) archives of known sex and age. The calculated multiple regression models showed a maximum R2 of 0.533 for females and 0.726 for males, with a high intra- and inter-observer agreement. The method suggested is considered not only useful for performing an identification profile during virtopsy, but also for application in further studies in order to attach a quantitative correlation for tissue ultrastructure characteristics, without complex and expensive methods beyond image analysis.

Sex determination in a Spanish population based on sacrum

Sex determination is one of the essential steps when it comes to establishing an individuals biological profile. It is important in both archaeology and forensic studies. The sacrum is not generally conserved, but in cases where it is, it can be used for determination of the sex of skeletal remains. Furthermore, the sacrum is not a commonly studied bone and has not been studied in a Spanish population. For this study, measurements of 170 sacra of individuals from the contemporary osteological collection of San José from Granada including only the adults were taken. Measurements based on the anatomical regions of the sacra were established in order to obtain some regression formulas to determine sex. Our results show that the Superior Transverse Line and Right Lateral Sacral Crest are the most dimorphic structures, achieving a 74% rate of correct classification of sex in a univariate analysis. In multivariate analysis, when the mentioned variables were combined, an 81.41% rate of correct classification was achieved. Our results show that our method can be applied with other methods at the same time to determine the sex of individuals in forensic and archaeological contexts.

Specific-age group sex estimation of infants through geometric morphometrics analysis of pubis and ischium

Sex determination of unknown individuals is one of the primary goals of Physical and Forensic Anthropology. The adult skeleton can be sexed using both morphological and metric traits on a large number of bones. The human pelvis is often used as an important element of adult sex determination. However, studies carried out about the pelvic bone in subadult individuals present several limitations due the absence of sexually dimorphic characteristics. In this study, we analyse the sexual dimorphism of the immature pubis and ischium bones, attending to their shape (Procrustes residuals) and size (centroid size), using an identified sample of subadult individuals composed of 58 individuals for the pubis and 83 for the ischium, aged between birth and 1year of life, from the Granada osteological collection of identified infants (Granada, Spain). Geometric morphometric methods and discriminant analysis were applied to this study. The results of intra- and inter-observer error showed good and excellent agreement in the location of coordinates of landmarks and semilandmarks, respectively. Principal component analysis performed on shape and size variables showed superposition of the two sexes, suggesting a low degree of sexual dimorphism. Canonical variable analysis did not show significant changes between the male and female shapes. As a consequence, discriminant analysis with leave-one-out cross validation provided low classification accuracy. The results suggested a low degree of sexual dimorphism supported by significant sexual dimorphism in the subadult sample and poor cross-validated classification accuracy. The inclusion of centroid size as a discriminant variable does not imply a significant improvement in the results of the analysis. The similarities found between the sexes prevent consideration of pubic and ischial morphology as a sex estimator in early stages of development. The authors suggest extending this study by analysing the different trajectories of shape and size in later ontogeny between males and females.

Validation methods of Fazekas and Kósa and Molleson and Cox for age estimation of the ilium in Western Mediterranean non-adult population: proposal of new regression formulas

The purpose of this study is to test the applicability of the age estimation methods of Fazekas and Kósa [1] and Molleson and Cox [2] in Western Mediterranean non-adults and to develop accurate and rapidly applied formulas for their age estimation, using a sample of 149 non-adults of known sex and age from the cemetery of San José in Granada (Spain). Measurements have been taken of the maximum length and width of each ilium for application of the formulas of Fazekas and Kósa [1] and Molleson and Cox [2]. There has been no significant intra- or inter-examiner variation in measurements. The documented age of the individuals has been underestimated with the Fazekas and Kósa method and overestimated with Molleson and Cox. Based on these findings, new formulas are proposed for the age estimation of non-adults in Western Mediterranean populations.