Inmaculada Alemán

Forensic age estimation on digital X-ray images: Medial epiphyses of the clavicle and first rib ossification in relation to chronological age.

Abstract:  In recent years, there has been a renewed interest in forensic sciences about forensic age estimation in living subjects by means of radiological methods. This research was conducted on digital thorax X‐rays to test the usefulness of some radiological changes in the clavicle and first rib. The sample consisted in a total of 123 subjects of Spanish origin (61 men and 62 women; age range: 5–75 years). From all subjects, a thorax posterior‐anterior radiograph was obtained in digital format. Scoring for fusion of medial epiphyses of the clavicle was carried out by Schmeling’s system and ossification of the costal cartilage of the first rib by Michelson’s system. Degree of ossification and epiphyseal fusion were analyzed in relation with known age and sex of these subjects. The results give a minimum age of >20 years for full fusion of the medial epiphysis of the clavicle (Stages 4 and 5). Concerning the first rib, all subjects with the final Stage 3 of ossification were above 25 years of age. These results suggest that the first rib ossification might become an additional method to the ones so far recommended for forensic age estimation in subjects around 21. New research would be desirable to confirm this suggestion.

Age estimation by pulp/tooth ratio in lower premolars by orthopantomography

Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Since 2004, in order to examine patterns of secondary dentine apposition, Cameriere et al. have been extensively studying the pulp/tooth area ratio of the canines by panoramic and peri-apical X-ray images. The main aim of this paper is to examine the relationship between age and age-related changes in the pulp/tooth area ratio in monoradicular teeth, with the exception of canines, by orthopantomography. A total of 606 orthopantomograms of Spanish white Caucasian patients (289 women and 317 men), aged between 18 and 75 years and coming from Bilbao and Granada (Spain), was analysed. Regression analysis of age of monoradicular teeth indicated that the lower premolars were the most closely correlated with age. An ANCOVA did not show significant differences between men and women. Multiple regression analysis, with age as dependent variable and pulp/tooth area ratio as predictor, yielded several formulae. R(2) ranged from 0.69 to 0.75 for a single lower premolar tooth and from 0.79 to 0.86 for multiple lower premolar teeth. Depending on the available number of premolar teeth, the mean of the absolute values of residual standard error, at 95% confidence interval, ranged between 4.34 and 6.02 years, showing that the pulp/tooth area ratio is a useful variable for assessing age with reasonable accuracy.

Forensic identification by computer-aided craniofacial superimposition: A survey

Craniofacial superimposition is a forensic process in which a photograph of a missing person is compared with a skull found to determine its identity. After one century of development, craniofacial superimposition has become an interdisciplinary research field where computer sciences have acquired a key role as a complement of forensic sciences. Moreover, the availability of new digital equipment (such as computers and 3D scanners) has resulted in a significant advance in the applicability of this forensic identification technique. The purpose of this contribution is twofold. On the one hand, we aim to clearly define the different stages involved in the computer-aided craniofacial superimposition process. Besides, we aim to clarify the role played by computers in the methods considered. In order to accomplish these objectives, an up-to-date review of the recent works is presented along with a discussion of advantages and drawbacks of the existing approaches, with an emphasis on the automatic ones. Future case studies will be easily categorized by identifying which stage is tackled and which kind of computer-aided approach is chosen to face the identification problem. Remaining challenges are indicated and some directions for future research are given.

Brief communication: the Granada osteological collection of identified infants and young children.

The objective of this study is to present the characteristics of a collection of identified infants and young children housed in the Laboratory of Anthropology of the University of Granada, Spain. The sample, which is still being enlarged, is currently composed of 230 complete skeletons aged from 5 months of gestation to 8 years, with a majority below 1 year. It mainly dates from the mid-20th century. The state of preservation is very good, and antemortem information is available from burial and death certificates, among other documents. Our sample makes an important contribution to the relatively few collections available in the world for investigating the osteological development of the skeletons of infants and young children from a physical anthropological perspective.

Sex estimation based on deciduous and permanent dentition in a contemporary Spanish population.

Sex estimation of skeletal remains with satisfactory allocation accuracy represents an essential step in reconstructing the biological profile of unknown individuals in archaeological research and forensic practice. Teeth are among the most frequently recovered physical elements of an individual that remain after death due to their hardness, durability, and resistance to postmortem insults. This study was based on the deciduous and permanent dentition of 269 individuals (150 males and 119 females) from the Granada osteological collection of identified infants, young children, and adults (Granada, Spain). Mesiodistal, buccolingual, and diagonal crown and cervical diameters of both dentitions were measured, and logistic regression analyses were performed to create equations for sex discrimination. The results show that the first and second deciduous molars and the permanent canines are the teeth with the greatest sexual dimorphism, providing percentages of correct assignment of sex between 78.1 and 93.1% in deciduous dentition and between 79.4 and 92.6% in permanent teeth, depending on the dimensions used. The results indicate that this method may be applicable as an adjunct with other accepted procedures for sex estimation when fragmentary skeletal remains are encountered in archaeological excavations and in forensic contexts.

Odontometric sex discrimination in the herculaneum sample (79 AD, Naples, Italy), with application to juveniles

Sex determination of subadult skeletal remains with satisfactory accuracy represents one of the most important limitations of archaeological research and forensic practice. Teeth are one of the most durable physical elements of an individual that remain after death, and constitute a potential source of information about the biological sex of that individual. This study was based on the skeletal remains of 117 individuals from the ancient city of Herculaneum (Naples, Italy), victims of the eruption of the nearby volcano Vesuvius on 24/25 August, 79 AD. It has been possible to develop discriminant function formulae based on dental dimensions of adult individuals whose sex had previously been determined based on descriptive osteologic criteria. These formulae were subsequently applied to the permanent dentitions of immature individuals of the same population in order to estimate their sex. The results show that the canine is the tooth with the greatest sex dimorphism in adults, providing percentages of correct assignment of sex between 76.5% and 100% depending on the dimension used. Of the 30 subadult individuals in the target sample, estimation of sex was possible for 22 individuals. Sex assignments matched those determined from descriptive characteristics of the ilia and mandible in 73.33% of the cases. The results provide some optimism that this method may be applicable to juvenile archaeological samples.

Computer vision and soft computing for automatic skull-face overlay in craniofacial superimposition

Craniofacial superimposition can provide evidence to support that some human skeletal remains belong or not to a missing person. It involves the process of overlaying a skull with a number of ante mortem images of an individual and the analysis of their morphological correspondence. Within the craniofacial superimposition process, the skull-face overlay stage just focuses on achieving the best possible overlay of the skull and a single ante mortem image of the suspect. Although craniofacial superimposition has been in use for over a century, skull-face overlay is still applied by means of a trial-and-error approach without an automatic method. Practitioners finish the process once they consider that a good enough overlay has been attained. Hence, skull-face overlay is a very challenging, subjective, error prone, and time consuming part of the whole process. Though the numerical assessment of the method quality has not been achieved yet, computer vision and soft computing arise as powerful tools to automate it, dramatically reducing the time taken by the expert and obtaining an unbiased overlay result. In this manuscript, we justify and analyze the use of these techniques to properly model the skull-face overlay problem. We also present the automatic technical procedure we have developed using these computational methods and show the four overlays obtained in two craniofacial superimposition cases. This automatic procedure can be thus considered as a tool to aid forensic anthropologists to develop the skull-face overlay, automating and avoiding subjectivity of the most tedious task within craniofacial superimposition.

Age-at-Death Estimation by Pulp⁄ Tooth Area Ratio in Canines: Study of a 20th-Century Mexican Sample of Prisoners to Test Cameriere's Method

Abstract:  Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Cameriere et al. studied the pulp/tooth area ratio by peri‐apical X‐ray images of the canines, to observe the apposition of secondary dentine. The present study examines the application of this technique in a Mexican identified sample coming from the Department of Physical Anthropology of the INAH, at Mexico City. The main aim of this work is to test the reliability of this method in a skeletal sample of a specific population, different from the samples used for its development. The obtained regression model explained 96.2% of total variance (R2 = 0.962) with a standard error of estimate of 1.909 and a standard deviation of 1.947. These results demonstrate great reliability and that the age/secondary dentine relationship is not variable in this specific population.

Craniofacial Superimposition in Forensic Identification using Genetic Algorithms

Craniofacial superimposition is a process that aims to identify a person by overlaying a photograph and a model of the skull. This process is usually carried out manually by forensic anthropologists; thus being very time consuming and presenting several difficulties in finding a good fit between the 3D model of the skull and the 2D photo of the face. In this paper we present a fast and automatic procedure to tackle the superimposition problem. The proposed method is based on real-coded genetic algorithms. Synthetic data are used to validate the method. Results on a real case from our Physical Anthropology lab of the University of Granada are also presented.

Sexual dimorphism of human sternum in a contemporary Spanish population.

Sex estimation is one of the first steps in forensic anthropology to identify human remains. In absence of the skull or the pelvis, any skeletal remain becomes fundamental for identification, especially in mass-disaster cases. The sternum is a potentially useful element in anthropological analysis with a high recovery rate in both forensic-and archaeological context. This study aims to develop classification functions for use in Spanish population. For this, sternum sexual dimorphism is studied in a sample of 105 individuals, known age-at-death, ancestry and sex, from San José Municipal Cemetery of Granada (Spain). Lins concordance correlation coefficient was used to estimate intra-and inter-observer error. In discriminant analysis for estimating sex, cross-validation shows accuracy rates exceeds 90% for sternum body length and maximum width (91.8%), or total length with maximum width (90.7%). Isolated variables with higher accuracy rates are total sternum length (89.1%), and sternum body length (87%). Although there is compliance with Hyrtls law it is not useful for estimating sex in Spanish population. These discriminant functions have also been validated successfully in two samples from Portugal (Coimbra identified skeletal collection--CISC, and 21st century identified ckeletal collection--Santarém XXI): the variables with higher accuracy rates sternum total length with its maximum width (92.3% the correctly classified individual in the sample CISC; and 83.5% in the sample of Santarém XXI) and the sternum total length (92.1% and 78.5%, respectively). The discriminant functions achieved with the collection of the San Jose cemetery of Granada can be applied to current remains, provided that study populations present a similar sexual dimorphism, like the two samples from Portuguese population presented in this study.