“Sex change” in skeletal remains: Assessing how heat-induced changes interfere with sex estimation

The true impact of heat-induced changes in human bone regarding their sex estimation has not been comprehensively documented having a potentially negative impact on forensic anthropology. The objective of this paper was to evaluate how heat exposure affects sex estimation based on both morphological and metric features. The study focused in both low-to-medium intensity burns and high intensity burns. Selected sexually dimorphic features were analysed in 51 experimentally burnt skeletons from the 21st Century Identified Skeletal Collection. Bones were burnt to maximum temperatures between 450 °C and 1050 °C achieved after 75 to 257 min. Morphological methods tested in this study comprised the recommendations for hipbone features from Buikstra and Ubelaker (1994) and from Bruzek (2002). On the other hand, metric references tested here were the ones from Wasterlain (2000), Curate et al. (2016) and Gonçalves et al. (2013) focused on the humerus, femur, calcaneus and talus. Agreement was tested with Gwet’s AC1 test and was further assessed by calculating the relative amount of perfect agreements. Results demonstrated that heat-induced changes affected not only the scoring of morphological features burnt at high temperatures but also the scoring of features burnt at lower intensities. On the other hand, metric features were only considerably affected in high intensity burns, no major changes being documented for low-to-medium intensity burns. For low-to-medium intensity burns, the Bruzek and Curate et al. methods revealed a better agreement between the pre- and post-burning scores. For high intensity burns, better agreement was obtained by using the Bruzek (2002) and Gonçalves et al. (2013) methods. As expected, heat-induced warping, fracture and metric change had a major impact on the pre- and post-observations’ agreement. Contrary to what has been systematically assumed over the years, this impact is also quite substantial in bones burnt at low-to-medium burn intensities so caution is advised during the analysis of this kind of burnt skeletal material.     

Application of the Suchey-Brooks method to three-dimensional imaging of the pubic symphysis

Age determination is a major field of interest in forensic anthropology. Among the different methods based on macroscopic skeletal study, the Suchey-Brooks method, which analyzes the pubic symphysis, is one of the most reliable. We applied the Suchey-Brooks method to three-dimensional computed tomographic reconstructions of the pubic symphysis. We demonstrated excellent agreement between the results of analysis of bone samples and those of the three-dimensional images, in particular regarding ridges of the articular surface and delimitation of the extremities. The accuracy of age estimation did not significantly differ (Wilcoxon test) between the Suchey-Brooks method applied to bones and the same method applied to CT images. Using high-quality images, this approach seems as reliable as the standard Suchey-Brooks method and offers several advantages: no bone preparation, no damage to bone material, and the possibility of application to living individuals.     

Determination of male age at death in Chinese Han population: using quantitative variables statistical analysis from pubic bones

Determination of age at death by skeletal features is difficult, but important, both in forensic and physical anthropology. Pubic symphysis is a widely accepted morphological indicator, which provides the best result for personal age identification. Age prediction in this study used nine indicators of morphological changes, viz: ridges and furrows on the symphysial surface, ridge of pubic tubercle, lower extremity, ventral beveling, ossific nodules, dorsal margin, ventral rampart, general macroscopic changes of symphysial surface, and bone density of the symphysial surface. Samples were drawn from 262 male individuals. The study procedures are as follows: Firstly, we examined the morphological features of pubic symphysis using criteria similar to Hanihara's and Suchey-Brooks (SB). Secondly, we evaluated each stage with an appropriate score. Thirdly, we deduced four equations of male age assessment of morphological features by statistic analysis. The results were compared with Hanihara's and Suchey-Brooks method; the similarities and differences among them were discussed objectively. The method produced consistent results as well as developing the criteria of Hanihara's and Suchey-Brooks'.     

Evaluation of the Suchey-Brooks method for aging skeletons in the Balkans

This study has been carried out to examine whether the Suchey-Brooks (S&B) methods could be successfully applied in age assessment of populations from the Balkans. The known-age sample consists of 33 females and 52 males pairs of pubic bones collected from the autopsy cases. Age estimation by S&B method showed an accuracy of 89.74% in males and 72.0% in females. Statistical analysis showed a positive correlation between the actual age of the investigated individuals and age phases obtained by the S&B method, although the mean values of the sixth age category differed significantly compared with the original model. The most reliable indicators in both sexes were the relief of the symphyseal surface, lipping, symphyseal rim, and dorsal margin. The discriminating power of these indicators was the least reliable in distinguishing S&B phases 2 and 3. Based on these results, the appropriate recommendations for aging Serbian populations are made. There was a good agreement between two observers (kappa=0.726).     

Assessing age-related morphology of the pubic symphysis from digital images versus direct observation

The increasingly global role of a forensic anthropologist necessitates a proper means for archiving evidence for re-examination. Large quantities of evidence can be stored and be made readily accessible through digital imaging. This study focuses on age assessment from digital photographs for personal identity reconstructions. A comparison of 52 Suchey-Brooks scores assigned to digital images and actual bone revealed that age assessment from digital images can be completed with accuracy. Coefficients of concordance imply that there significant agreement between osteological assessment of aging criteria from digital images and direct observation-greater than random change alone (p < 0.05). However, assessments from images should be approached with caution since there are inherent limitations of the naked eye in identifying morphological changes in certain skeletal features, especially where older adults are concerned. Although there is no replacement for a hands-on physical assessment, a digital archive may facilitate the global needs of the forensic anthropologist.     

A Comparison Between Digital Radiography,Computed Tomography,and Magnetic Resonance in the Detection of Gunshot Residues in Burnt Tissues and Bone

The radiological search for GSR is crucial in burnt material although it has been rarely tested. In this study, thirty‐one bovine ribs were shot at near‐contact range and burnt to calcination in an oven simulating a real combustion. Computed tomography (CT) and magnetic resonance (MR) were performed before and after carbonization and compared with former analyses with DR (digital radiography); thus comparing the assistance, the radiological methods can provide in the search for GSR in fresh and burnt bone. DR demonstrated the greatest ability in the detection of metallic residues, CT showed lower abilities, while MR showed a high sensitivity only in soft tissues. Thus, DR can be considered as the most sensitive method in the detection of GSR in charred bones, whereas CT and MR demonstrated much less reliability. Nonetheless, the MR ameliorates the analysis of gunshot wounds in other types of remains with large quantities of soft tissues.     

Auricular surface aging: a blind test of the revised method on historic Italians from Sardinia

Age determination from human skeletal remains is an important biological parameter in both forensic and bioarchaeological contexts. This study presents the results of a blind test of the revised auricular surface age estimation method proposed by Buckberry and Chamberlain (Am. J. Phys. Anthropol. 119 (2002) 321-329) on a large sample (n=404) of known sex and age from the Sassari collection, housed at the Museum of Anthropology, University of Bologna, Italy. Ilia were scored for five features: transverse organization, surface texture, microporosity, macroporosity, and apical changes, which combined for a composite score. The results indicated that all features and the composite score were positively correlated with known age. Composite scores were significantly different between the sexes, suggesting that males and females should be treated separately. Bias and inaccuracy varied across age intervals. Age tended to be overestimated in individuals under age 59 and underestimated for those over age 60 years. However, the revised method showed improvement over the original auricular surface method (Lovejoy et al., Am. J. Phys. Anthropol. 68 (1985) 15-28), especially for aging older individuals. Considerable variation exists in the age ranges derived from composite scores and few significant differences were found between age stages, suggesting that fewer stages with wider age ranges may be necessary. The independent, quantitative scoring of the surface features makes the revised method substantially easier to apply and the method shows significant improvement for aging older individuals.     

Differential burns of head and pubic hair

A woman, who was hospitalized with extensive burns in the genital and perineal region, accused her husband who lived apart from her to have inflicted the injuries with a lighter and a burning candle out of jealousy. The husband denied the accusations and stated that he wanted to singe off the pubic hair with the lighter during sadomasochist sexual practices performed in mutual agreement. As he did so extensive flames suddenly developed--something he had not expected--thus causing the burns. To check the statement cut off tufts of head and pubic hair were set on fire with a lighter to compare their burning behaviour. Pubic hair was easily inflammable and burnt almost completely within about 10 seconds developing up to 10 cm high flames, whereas straight head hair developed only minor flames and the singed hairs stopped burning spontaneously some seconds later already.     

Evaluation of cast methods for estimating age from the os pubis.

Age-related changes of the pubic symphysis have gained wide acceptance among physical anthropologists as one basis for estimating adult skeletal age. However, these methods have not been tested by independent observers on large samples with known ages at death that represent contemporary populations. In this study 202 female and 116 male pairs of pubes collected at autopsy were blindly evaluated for age using the McKern-Stewart or Gilbert-McKern and Suchey-Brooks methods. Performance of the methods was measured by mean absolute deviation of true age from scored interval means and frequencies of true age falling within +/- 1 and +/- 2 standard deviations from the mean. The results suggest that the Suchey-Brooks methods are superior in forensic applications and that the racially specific refinement for males should be used. Age estimates should include +/- 2 standard deviations, and chances of error should be considered, especially when advanced age or debilitation is suspected.     

Quantitative Analysis of the Morphological Changes of the Pubic Symphyseal Face and the Auricular Surface and Implications for Age at Death Estimation

Age estimation methods are often based on the age‐related morphological changes of the auricular surface and the pubic bone. In this study, a mathematical approach to quantify these changes has been tested analyzing the curvature variation on 3D models from CT and laser scans. The sample consisted of the 24 Suchey–Brooks (SB) pubic bone casts, 19 auricular surfaces from the Buckberry and Chamberlain (BC) “recording kit” and 98 pelvic bones from the Terry Collection (Smithsonian Institution). Strong and moderate correlations between phases and curvature were found in SB casts (ρ 0.60–0.93) and BC “recording kit” (ρ 0.47–0.75), moderate and weak correlations in the Terry Collection bones (pubic bones: ρ 0.29–0.51, auricular surfaces: ρ 0.33–0.50) but associated with large individual variability and overlap of curvature values between adjacent decades. The new procedure, requiring no expert judgment from the operator, achieved similar correlations that can be found in the classic methods.     

Determining the human origin of fragments of burnt bone: a comparative study of histological, immunological and DNA techniques.

In situations where badly burnt fragments of bone are found, identification of their human or non-human origin may be impossible by gross morphology alone and other techniques have to be employed. In order to determine whether histological methods were redundant and should be superseded by biomolecular analyses, small fragments of artificially burnt bone (human and non-human) were examined by quantitative and standard light microscopy, and the findings compared with newer biomolecular analyses based on identifying specific human albumin by ELISA and amplifying human mitochondrial DNA by PCR. For quantitative microscopy, reference data were first created using burnt bones from 15 human and 20 common domestic and farm animals. Measured osteon and Haversian canal parameters were analysed using multivariate statistical methods. Highly significant differences were found between values for human and non-human bone, and a canonical discriminant function equation was derived, giving a predicted correct classification of 79%. For the main study, samples of cortical bone were taken from three fresh cadavers, six human skeletons and ten freshly slaughtered animals and burnt by exposure to temperatures ranging from 800 to 1200 degrees C; charred fragments of human cortical bone from two forensic cases were also tested. Quantitative microscopy and canonical discriminant function gave the correct origin of every sample. Standard microscopy falsely assigned burnt bone from one human skeleton and one forensic case to a non-human source, but otherwise gave correct results. Human albumin was identified in five individuals, including one of the forensic cases, but mitochondrial DNA could not be amplified from any of the human bone. No false positive test results were seen with either biomolecular method; and human albumin and mitochondrial DNA were correctly identified in all unburnt control specimens. It was concluded that histological methods were not redundant and that quantitative microscopy provided an accurate and consistent means of determining the human or non-human origin of burnt bone and was more reliable than standard microscopy or the newer immunological and DNA techniques tested here.     

Reassembling scattered and mixed human bones by trace element ratios

Trace metal ratios in human bones were examined to determine if there were ratios that were sufficiently consistent within an individual yet varying sufficiently from the bones of another individual so that bones in a mixed grave could be reassembled. The concentrations of 21 elements sampled at 54 places on 30 human bones in each of 5 skeletons indicated that the magnesium/zinc ratio was the most reliable and that the zinc/sodium, magnesium/sodium, and chromium/sodium ratios could be used as supplements to help reassemble human bones belonging to the same individual after all standard techniques had been used.     

Morphology of fractures of long tubular bones in children upon trauma due to solid blunt objects

Morphologic features of diaphyseal fractures of lond tubular bones in different age groups in childhood were studied experimentally on biodummy using direct stereomicroscopy (MBC-9). Blow effect was induced by solid blunt objects at the middle diaphyseal parts at a right angle. A series of specific morphologic features which help to diagnose the specific bone tissue lesions in different fracture zones as well as in different age periods was obtained. Experimental data were confirmed by expert observations which proves the possibility of using these specific morphologic features of diaphyseal fractures of long tubular bones in childhood for medicolegal purposes.     

The Effect of Soft Tissue on Temperature Estimation from Burnt Bone Using Fourier Transform Infrared Spectroscopy

This study investigated the effect of soft tissue and different exposure times on the prediction of burning temperatures of bone when using Fourier transform infrared spectroscopy (FTIR). Ovis aries rib bones were burnt at different temperatures and for varying time intervals. Results of a linear regression analysis indicated that burn temperatures can be predicted with a standard error of ±70°C from defleshed bone spectra. Exposure time does not have a significant impact on prediction accuracy. The presence of soft tissue has a significant impact on heat‐induced changes of the bone matrix in low (<300°C) as well as high temperatures (>800°C), slowing down combustion in the former and accelerating it in the latter (p < 0.05). At medium temperatures, no significant difference was noted. These results provide forensic investigators a new perspective with which to interpret the results of crystallinity measures derived from burnt bone.     

Differentiation of traumatic and heat-induced dental tissue fractures via SEM analysis

Previous studies have examined the effects of heating on teeth; however, none have identified characteristics that allow analysts to differentiate traumatic from heat-induced fractures. This study examined our ability to discern notable differences in preincineration traumatic fractures and heat-induced fractures in postincineration dentition. Twelve anterior dental specimens were subjected to blunt force trauma while a second set were not. All 24 samples were then incinerated in a muffle furnace at a peak temperature (900°C) consistent with house fires. The specimens were subsequently examined with a scanning electron microscope to identify and compare heat-induced and traumatic fractures. The results obtained during examination yielded no differences between the features displayed by specimens that had been inflicted with preincineration trauma and those that did not. Unlike bone, distinguishing features for the differentiation of traumatic and heat-induced fractures could not be compiled.     

Pubic bone age estimation in adult women

In recent years, numerous physical anthropologists have pointed out the need for regional standards for estimating age in various world populations. While investigating aging methods for East European populations, dramatic changes were noted in the pubic symphyseal morphology and structure of older adult female individuals. These changes were not captured in the typically used pubic symphysis aging methods. This paper defines and tests the need for a new phase, phase VII, that follows the Suchey-Brooks phase VI. In addition, Suchey-Brooks phases V and VI are redefined. Phase definitions, decision-making rules, and comparison graphics for the new method are presented. Balkan (n = 85) and Eastern Tennessee (n = 104) samples, totaling 189 individuals, were used in the analysis. Pearson correlation coefficients between four observers and a control seriation were strong, indicating ease of replicability between investigators. No statistically significant intra-observer error was detected. Summary statistics show that individuals in phase V were on average in the early 50s, while individuals in phase VI were in their mid 50s to mid 60s, and individuals in phase VII were in their mid 70s. Since linear regression models tend to under-age the elderly and over-age the young, transition analysis, using an unrestricted cumulative probit model, was undertaken to evaluate the phases and to produce point estimates for the ages-at-transition for the Balkan sample. The highest posterior density region point estimates with their associated upper and lower bounds can be used for predicting age for unknown forensic cases related to the Balkan sample. Further, the mean ages and standard deviations for phases V-VII for the Tennessee sample are presented for use in American forensic cases.     

Chemical trace XRF analysis to detect sharp force trauma in fresh and burned bone

Forensic anthropologists may not always be able to differentiate heat-induced fractures from fractures with other aetiologies, namely sharp force traumas, with clear nefarious impact on medico-legal conclusions. The objective of this study was to experimentally investigate if blade chemical traces are transferred to defleshed bone tissue and if they remain there after a burning event. This was accomplished by prompting sharp force traumas in 20 macerated fresh pig ribs with five different instruments, namely a stainless steel knife, an artisanal knife and a ceramic kitchen knife, a small axe and a large axe. Another pig rib was used as control, not being subjected to any trauma. All instruments were probed by X-ray fluorescence (XRF) to establish the composition of each blade. Bone samples, both pre-burned and post-burned (at 500 °C, 700 °C, 900 °C and 1100 °C), were then probed by XRF. All sharp force instruments left detectable chemical traces on pre-burned bone, although not in all samples. Furthermore, traces were still detected after experimental burning in most cases. Potentially, XRF can provide relevant information about the aetiology of fractures in burned and unburned bones, although the effect of soft tissues and diagenesis must still be investigated.     

Determination of some somatic body dimensions by osteometric foot measurements

Methods of diagnosis of somatic life-time peculiarities of man (body height, shoulders breadth and dimensions of extremities and their segments) were elaborated on the basis of a study of interrelations between the human body-built features, on the one hand, and measurement characteristics of the foot, on the other hand, by using the modern programs of multi-measurement statistics. Isolated skeleton bones of osseous complexes and fragments of native and burnt bones were the research objects. Footwear and cloths items, which belonged to an actual missing person, can be identification objects. The paper is primarily addressed to forensic medical experts and can be useful for criminalists, anthropologists and archeologists.     

A Test of a Recently Devised Method of Estimating Skeletal Age at Death using Features of the Adult Acetabulum

Estimation of age at death from adult skeletal remains is highly problematic, due in great part to interpopulation variability in skeletal age changes. Thorough testing of aging methods is therefore of key importance. A method recently devised by Calce (Am J Phys Anthropol 148 (2012): 11–23) for placing adult skeletons into three broad age at death classes (17–39, 40–64, 65+ years) on the basis of acetabular morphology is tested on a collection of 18–19th century AD skeletons (N = 185) of documented age at death from London. Results showed that 45% were correctly assigned to age class using this method. This compares with 81% reported by Calce on 20th century North American material. This indicates significant interpopulation differences in the relationship between the Calce acetabular variables and age, even between populations of European ancestry. Until the sources of this variation are better understood, caution should be used before applying this method to estimate age in unknown skeletons.     

A novel approach to the visualisation of heat-induced structural change in bone.

A new approach to visualising heat-induced change in bone was attempted. This was an attempt to counter the serious limitations of existing analytical methods yet still allow for the examination of subtle changes that occur due to burning. A new form of Magnetic Resonance Imaging was deemed to fulfil this remit. Preliminary tests were performed and proved successful in creating clear, well-defined images of progressive heat-induced structural changes in bone. The implications for improving our understanding of heat-induced change, and therefore our methods of human identification, are significant.