RESUMEN
The objectives of this work were to validate two published methods for subadult age estimation based on measurements of the pars lateralis, and to develop a new method based on a wider set of measurements using the Granada Osteological Collection. The pars lateralis of 127 individuals from 6 months prenatal to 4 years of age were measured, taking 6 measurements of the body, the anterior synchondrosis and the condyle. Length and width were used to validate the published methods. Regression functions using age as the independent variable were calculated using each of the six measurements taken, and functions for age estimation were obtained through classical calibration. Functions for calculation of the 95% confidence interval of the estimates were obtained through linear regression using the estimation errors. In the validation of the previous methods, one method showed a linear tendency of the differences, which can be attributed to a circularity in reasoning in the original work. In the other method, a tendency towards overestimation was found, which can be attributed to the limitations of the method itself. The new functions have a consistency rate of 92.2% to 97.1%; the functions derived from all measurements are useful from 6 months prenatal to 2 years of age. Moreover, the functions obtained are applicable to incomplete pars lateralis, allowing for age estimation in a wide set of contexts and providing straightforward age estimates with their respective margin of error.
Asunto(s)
Restos Mortales , Porción Reticular de la Sustancia Negra , Huesos , Femenino , Antropología Forense , Humanos , Lactante , Modelos Lineales , EmbarazoRESUMEN
In the context of physical and forensic anthropology, when a child's skeleton is damaged or in poor condition, which is common, many of the metric methods for the estimation of skeletal age cannot be used. In these circumstances, those more resistant bones, such as the pars basilaris, will be most useful. The aims of this study were to test existing methods for estimating skeletal age from the metric study of the pars basilaris and to propose new regression formulae. One hundred fourteen individuals aged between 5 months of gestation and 6 years were analyzed; seven measures were taken from each pars basilaris using a digital caliper. The chronological age was compared with the estimated age using the methods published by Fazekas and Kósa in 1978 and by Scheuer and MacLaughlin in 1994. New regression formulae are proposed, obtained by classical calibration, which include confidence intervals at 50 and 97.5 % to express the error. With both methods, significant differences were observed; the method of Fazekas and Kósa shows a tendency to underestimate the age, and the method of Scheuer and MacLaughlin tends to overestimate it. The proposed formulae represent a good tool for estimating age in many different contexts because they are relatively easy to apply, although other analysis systems, such as Bayesian approach or geometric morphometry, offer more robust and effective results.
Asunto(s)
Determinación de la Edad por el Esqueleto/métodos , Hueso Occipital/crecimiento & desarrollo , Análisis de Regresión , Niño , Preescolar , Femenino , Antropología Forense , Humanos , Lactante , Recién Nacido , MasculinoRESUMEN
Sex estimation of juveniles in the Physical and Forensic Anthropology context is currently a task with serious difficulties because the discriminatory bone characteristics are minimal until puberty. Also, the small number of osteological collections of children available for research has made it difficult to develop effective methodologies in this regard. This study tested the characteristics of the ilium and jaw proposed by Schutkowski in 1993 for estimation of sex in subadults. The study sample consisted of 109 boys and 76 girls, ranging in age from 5 months of gestation to 6 years, from the identified osteological collection of Granada (Spain). For the analysis and interpretation of the results, we have proposed changes from previous studies because we believe they raised methodological errors relating to the calculation of probabilities of success and sex distribution in the sample. The results showed correct assignment probabilities much lower than those obtained by Schutkowski as well as by other authors. The best results were obtained with the angle and depth of the sciatic notch, with 0.73 and 0.80 probability of correct assignment respectively if the male trait was observed. The results obtained with the other criteria were too small to be valid in the context of Physical or Forensic Anthropology. From our results, we concluded that Schutkowski method should not be used in forensic context, and that the sciatic notch is the most dimorphic trait in subadults and, therefore, the most appropriate to develop more effective methods for estimating sex.