Forensic age estimation of the knee by post-mortem DR, CT, and MR imaging: a comparative study.

It is believed by many that reference data for age estimation purposes must be imaging-modality specific. A study from our department has however proven otherwise. We therefore found it interesting to investigate this further by looking at the level of agreement between different imaging modalities. The aim of this study was to investigate the level of agreement between the three radiological modalities, computed tomography (CT), magnetic resonance imaging (MRI), and digital radiography (DR), in assessing the ossification of the epiphyses of the knee. A total of 34 deceased individuals of 10-25 years of age, brought in for a medicolegal autopsy at our department, were scanned by CT, MRI, and DR. The ossification stages of the three bones of the right knee, distal femoral, proximal tibial, and proximal fibular epiphysis were assessed using the established combined staging method by Schmeling et al. and Kellinghaus et al. Analysis of the results by Cohen's weighted kappa showed a good agreement between CT and DR (K = 0.61-0.70), and MRI and DR (K = 0.68-0.79) but only moderate agreement between CT and MRI (K = 0.55-0.57). This leads us to conclude that different radiological images cannot be used interchangeably for age estimation purposes, so reference material needs to be imaging-modality specific. However, to make a more general conclusion research on a larger population is needed.

Age assessment in unaccompanied minors: assessing uniformity of protocols across Europe.

Age assessment of migrants is crucial, particularly for unaccompanied foreign minors, a population facing legal, social, and humanitarian challenges. Despite existing guidelines, there is no unified protocol in Europe for age assessment.The Forensic Anthropology Society of Europe (FASE) conducted a comprehensive questionnaire to understand age estimation practices in Europe. The questionnaire had sections focusing on the professional background of respondents, annual assessment numbers, requesting parties and reasons, types of examinations conducted (e.g., physical, radiological), followed protocols, age estimation methods, and questions on how age estimates are reported.The questionnaire's findings reveal extensive engagement of the forensic community in age assessment in the living, emphasizing multidisciplinary approaches. However, there seems to be an incomplete appreciation of AGFAD guidelines. Commonalities exist in examination methodologies and imaging tests. However, discrepancies emerged among respondents regarding sexual maturity assessment and reporting assessment results. Given the increasing importance of age assessment, especially for migrant child protection, the study stresses the need for a unified protocol across European countries. This can only be achieved if EU Member States wholeheartedly embrace the fundamental principles outlined in EU Directives and conduct medical age assessments aligned with recognized standards such as the AGFAD guidelines.

The usefulness of a trauma probability of survival model for forensic life-threatening danger assessments.

Clinical forensic medical examinations constitute an increasing proportion of our institution's tasks, and, concomitantly, the authorities are now requesting forensic life-threatening danger assessments based on our examinations. The aim of this retrospective study was to assess if a probability of survival (PS) trauma score could be useful for these forensic life-threatening danger assessments and to identify a cut-off PS score as a supporting tool for the forensic practice of assessing life-threatening danger. We compared a forensic database and a trauma database and identified 161 individuals (aged 15 years or older) who had both a forensic life-threatening danger assessment and a PS score. The life-threatening danger assessments comprised the following statements: was not in life-threatening danger (NLD); could have been in life-threatening danger (CLD); or was in life-threatening danger (LD). The inclusion period was 2012-2016. A statistically significant difference was found in the PS scores between NLD, CLD and LD (chi-square test: p < 0.0001). The usefulness of the PS score for categorizing life-threatening danger assessments was determined by a receiver-operator characteristic (ROC) curve. The area under the curve was 0.76 (95% CI, 0.69 to 0.84) and the ROC curve revealed that a cut-off PS score of 95.8 would appropriately identify LD. Therefore, a PS score below 95.8 would indicate life-threatening danger. We propose a further exploration of how the evidence-based PS score, including a cut-off value, might be implemented in clinical forensic medical statements to add to the scientific strength of these statements.

Life-threatening danger assessments of penetrating injuries in Eastern Danish clinical forensic medicine.

Clinical forensic assessments of injuries' life-threatening danger may have an impact on the legal aftermath following a violent assault. The pursuit of evidence-based guidelines should ensure a user-independent and reproducible forensic practice. However, does it? The aim of this study was to evaluate the forensic life-threatening danger assessments after a protocol implementation in 2016. The evaluation concerned usability and reproducibility of the protocol, and its influence on assessment severity. We analyzed the level of inter- and intra-rater agreement using 169 blinded, prior-protocol cases that were reassessed by two forensic specialists. We compared assessment made the year before and after protocol implementation (n = 262), and the forensic specialists' reassessments with the prior-protocol cases' original assessments (n = 169). Whether to make an assessment, the levels of agreement varied between weak agreement (inter-rater, Κ = 0.43; assessor 1, Κ = 0.57) and strong agreement (assessor 2, Κ = 0.90). Regarding severity, the levels of agreement varied between strong agreement (inter-rater, Κ = 0.87; assessor 1: Κ = 0.90) and almost perfect agreement (assessor 2: Κ = 0.94). The assessments were statistically significant redistributed after the implementation (chi-square test: p < 0.0001). The proportion of cases assessed as having not been in life-threatening danger increased from 9 to 43%, and moderate severity assessments decreased from 55 to 23%. Of the moderate severity assessments, 55% were reassessed as having not been in life-threatening danger. The protocol ensured independent and reproducible assessments when the forensic specialists agreed on making one. The protocol resulted in less severe assessments. Future studies should examine the reliability of the protocol and its consequences for legal aftermaths.

Population genomics of Bronze Age Eurasia.

The Bronze Age of Eurasia (around 3000-1000 BC) was a period of major cultural changes. However, there is debate about whether these changes resulted from the circulation of ideas or from human migrations, potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic structure in both Europe and Asia. Our findings are consistent with the hypothesized spread of Indo-European languages during the Early Bronze Age. We also demonstrate that light skin pigmentation in Europeans was already present at high frequency in the Bronze Age, but not lactose tolerance, indicating a more recent onset of positive selection on lactose tolerance than previously thought.

Leprosy in medieval Denmark: Exploring life histories through a multi-tissue and multi-isotopic approach.

OBJECTIVES: By focusing on two Danish leprosaria (Naestved and Odense; 13th-16th c. CE) and using diet and origin as proxies, we follow a multi-isotopic approach to reconstruct life histories of patients and investigate how leprosy affected both institutionalized individuals and the medieval Danish community as a whole. MATERIALS AND METHODS: We combine archaeology, historical sources, biological anthropology, isotopic analyses (δ13 C, δ15 N, δ34 S, 87 Sr/86 Sr) and radiocarbon dating, and further analyze bones with different turnover rates (ribs and long bones). RESULTS: The δ13 C, δ15 N and δ34 S results indicate a C3 terrestrial diet with small contributions of marine protein for leprosy patients and individuals from other medieval Danish sites. A similar diet is seen through time, between males and females, and patients with and without changes on facial bones. The isotopic comparison between ribs and long bones reveals no significant dietary change. The δ34 S and 87 Sr/86 Sr results suggest that patients were local to the regions of the leprosaria. Moreover, the radiocarbon dates show a mere 50% agreement with the arm position dating method used in Denmark. CONCLUSIONS: A local origin for the leprosy patients is in line with historical evidence, unlike the small dietary contribution of marine protein. Although only 10% of the analyzed individuals have rib/long bone offsets that undoubtedly show a dietary shift, the data appear to reveal a pattern for 25 individuals (out of 50), with elevated δ13 C and/or δ15 N values in the ribs compared to the long bones, which points toward a communal type of diet and reveals organizational aspects of the institution.

Ancient human parvovirus B19 in Eurasia reveals its long-term association with humans.

Human parvovirus B19 (B19V) is a ubiquitous human pathogen associated with a number of conditions, such as fifth disease in children and arthritis and arthralgias in adults. B19V is thought to evolve exceptionally rapidly among DNA viruses, with substitution rates previously estimated to be closer to those typical of RNA viruses. On the basis of genetic sequences up to ∼70 years of age, the most recent common ancestor of all B19V has been dated to the early 1800s, and it has been suggested that genotype 1, the most common B19V genotype, only started circulating in the 1960s. Here we present 10 genomes (63.9-99.7% genome coverage) of B19V from dental and skeletal remains of individuals who lived in Eurasia and Greenland from ∼0.5 to ∼6.9 thousand years ago (kya). In a phylogenetic analysis, five of the ancient B19V sequences fall within or basal to the modern genotype 1, and five fall basal to genotype 2, showing a long-term association of B19V with humans. The most recent common ancestor of all B19V is placed ∼12.6 kya, and we find a substitution rate that is an order of magnitude lower than inferred previously. Further, we are able to date the recombination event between genotypes 1 and 3 that formed genotype 2 to ∼5.0-6.8 kya. This study emphasizes the importance of ancient viral sequences for our understanding of virus evolution and phylogenetics.

Enlargement of the human adrenal zona fasciculata and chronic psychiatric illness - an autopsy-based study.

Severe mental illness (SMI) is associated with a reduced life expectancy of up to 20 years. One possible contributor to this fact is dysregulation of the hypothalamus-pituitary-adrenal (HPA)-axis. Looking at the morphology of effector organs, such as the adrenal glands themselves, could reveal insights into organ function and response to possible HPA-dysregulation. This forensic autopsy-based study investigated if there were any morphological changes in adrenal glands between decedents who had previously been submitted to a psychiatric hospital with a diagnosis of schizophrenia (n = 34), bipolar (n = 5), or depressive disorder (n = 20), any other psychiatric diagnosis (n = 36) compared with decedents who had no previous psychiatric admission (n = 40). Length of admissions to psychiatric wards and admission in the 180 days preceding death was included in regression as proxy variables for severity of illness. On the macroscopic level, we found no difference in gland weight or volume. On the microscopic level, we found a 25% increase in cross-sectional area of the zona fasciculata (ZF) in decedents who had a diagnosis of schizophrenia compared with controls (p = 0.033). Other diagnosis groups did not differ from controls. Total admission length was positively correlated with area of the ZF.Lay SummaryPeople with a severe mental disorder may be in a constant state of increased stress, which is harmful. This study looked at the adrenal gland, which produces stress hormones, to see if they were different in deceased persons who had suffered from a severe mental illness. We found that the part of the adrenal gland that produces stress hormones is larger in deceased patients who suffered from schizophrenia, but not other types of psychiatric illnesses, compared to deceased persons with no history of psychiatric illness.

Comparison of hippocampal volume measurement by autopsy and post-mortem magnetic resonance imaging.

We present an autopsy-validated, non-invasive, magnetic resonance imaging (MRI) based segmentation algorithm, for determining hippocampal volume. A segmentation algorithm was developed to assess the volume of the hippocampus. Deceased individuals with severe mental illness were used to evaluate the use of MRI imaging to determine hippocampal volume as this group has previously been associated with altered hippocampal volume diagnosed on MRI. The accuracy of the MR- scanning protocol for volume measurement was tested on a water filled phantom control with a known volume of 500 ml, and a difference of 0.08% was found. Thus the scanning protocol was deemed to have produced acceptable results when comparing volume measures of a pair of segmented hippocampi obtained at the 1 T MR scanner and a 3 T MR scanner using the software program Mimics®. The segmentation algorithm was tested by a volume comparison obtained using anterior and posterior landmarks (in situ) and the exact volume of the dissected hippocampus (ex situ). The in situ and ex situ hippocampal volumes were highly correlated; R2 was 96%, with a mean difference of 4-5%. Cases were also examined for intra- and inter-observer agreement. This study presents a validated segmentation algorithm that can be used to determine the hippocampal volume using post-mortem MR and anatomical landmarks.

Odontological identification dental charts based upon postmortem computed tomography compared to dental charts based upon postmortem clinical examinations.

Since the beginning of this century, the use of postmortem computed tomography (PMCT) in forensic autopsies has increased. In this study we examined how similar dental charts created using PMCT as a solitary examination mode were to dental charts created using the conventional method of a clinical inspection including intraoral radiographs. A total of 100 previously performed dental identification cases were retrospectively included in the study. For each case, a dental chart was created solely based upon PMCT. The PMCT based dental chart was subsequently compared with the chart created from the previous conventional identification examination. Based upon the accuracy, sensitivity and specificity values PMCT performed very well compared to the conventional method in the identification concerning presence or absence of teeth, the presence of crowns, bridges and endodontic treatments as well as the presence and types of fillings. PMCT performed poorly concerning the extension of fillings and identification of small, tooth-colored fillings. The use of PMCT is a valuable supplement to the conventional methods available for forensic odontologists and may be of great value for initial screening in mass fatalities.

Evaluating osteological ageing from digital data.

Age at death estimation of human skeletal remains is one of the key issues in constructing a biological profile both in forensic and archaeological contexts. The traditional adult osteological methods evaluate macroscopically the morphological changes that occur with increasing age of specific skeletal indicators, such as the cranial sutures, the pubic bone, the auricular surface of the ilium and the sternal end of the ribs. Technologies such as computed tomography and laser scanning are becoming more widely used in anthropology, and several new methods have been developed. This review focuses on how the osteological age-related changes have been evaluated in digital data. First, the 3D virtual copies of the bones have been used to mimic the appearance of the dry bones and the application of the traditional methods. Secondly, the information directly extrapolated from CT scans has been used to assess qualitatively or quantitatively the changes of the trabecular bones, the thickness of the cortical bones, and to perform morphometric analyses. Lastly, the most innovative approach has been the mathematical quantification of the changes of the pelvic joints, calculating the complexity of the surface. The importance of new updated reference datasets, created thanks to the use of CT scanning in forensic settings, is also discussed.

Forensic 3D documentation of skin injuries using photogrammetry: photographs vs video and manual vs automatic measurements.

Accurate and precise documentation of lesions is an important aspect of the forensic pathologists' work. Photogrammetry provides a useful tool to take precise measurements from photographs. These photographs are normally acquired with single camera photographs, but the procedure is quite time-consuming. Video recording has the potential to record a larger amount of image data faster. We documented 33 cadaveric skin lesions, using photographs and video recordings. The dimensions of the lesions ranged between 0.27 and 21.8 cm. The measurements of the lesions were extracted with both manual and automatic point measurements from photographs and from video frames, respectively. Very small differences (mean and median < 1 mm) were found between measurements taken in photographs versus video frames. Video frames were often blurred, preventing clear demarcation of the edges of the lesions and presenting a larger amount of noise in the 3D models. The differences between the manual point and automatic point measurements were very small (mean and median < 1 mm), but the manual procedure is to be preferred, since automatic points were not always located on the edges of the lesions. The only aspect in which video frames were superior to photographs was the recording time: video recording was almost five times faster than the photo sessions. In conclusion, this study shows that precise and comparable measurements can be extracted both from photographs and video frames. The video is the fastest method, but the use of photographs is still recommended. Manual measurements are more precise than automatic measurements and equally time-consuming.

Coronary artery CT calcium score assessed by direct calcium quantification using atomic absorption spectroscopy and compared to macroscopic and histological assessments.

The Agatston score (AS) is the gold standard CT calcium scoring method in clinical practice. However, the AS is an indirect method of determining calcium amount, whereas atomic absorption spectroscopy (AAS) can directly measure the calcium amount. Our primary aim was to investigate the association between the AS and the coronary calcium amount measured by AAS. Furthermore, we compared our outcome to the macroscopic and histological coronary calcification and stenosis assessment, thus allowing us to infer a clinical coronary artery status based on post-mortem findings. Deceased individuals were examined with a 64-slice multidetector CT scanner, and the AS was determined. At autopsy, the degree of CAC and stenosis was determined, and the coronary arteries were excised and weighed. The coronary arteries were decalcified in a solution that was examined using AAS to measure the calcium amount. The degree of CAC and stenosis was also assessed by a histological examination. One hundred thirty-two coronary arteries were examined, and AS was highly correlated to the coronary calcium amount, measured by AAS, (r2 = 0.72, Pearson 0.85, p < 0.0001). In cases with AS 0, AAS measurements showed zero or very low calcium amounts. AS was also correlated to macroscopic and histological calcification assessments (Spearman's rho 0.68, p < 0.0001, Spearman's rho 0.82, p < 0.0001). Furthermore, an underestimation of subclinical atherosclerosis was seen and AS 0 could not rule out stenosis.

Cardiac left ventricular myocardial tissue density, evaluated by computed tomography and autopsy.

BACKGROUND: Left ventricular mass (LVM) is an independent risk factor for the prediction of cardiac events. Its assessment is a clinically important diagnostic procedure in cardiology and may be performed by Computed Tomography (CT). The aim of this study was to assess the correlation between the cardiac left ventricular shell volume (LVShV) determined by postmortem Computed Tomography (PMCT) and the anatomic LVM obtained at autopsy and to calculate the myocardial tissue density. METHODS: A total of 109 deceased individuals were examined with a 64-slice CT scanner and LVShV was determined. At autopsy, the left ventricle was dissected and weighted. The correlation between LVShV and the anatomic LVM was analysed. Asymmetric left ventricular (LV) hypertrophy was recorded. Inter-observer variability was evaluated, and a density value for myocardial tissue was calculated. RESULTS: The mean age of the deceased was 55 ± 16 years, and 58% was men. We found 30 cases of asymmetric LV hypertrophy. A highly positive correlation existed between LVShV and anatomic LVM (r = 0.857; p < 0.0001), regardless of hypertrophy, asymmetric hypertrophy and gender. The mean difference in the inter-observer variability for LVShV assessment was - 4.4 ml (95% CI: -26.4; 17.6). A linear regression analysis was performed, resulting in a value of 1.265 g/ml for myocardial tissue density. Applying the hitherto used myocardial tissue density of 1.055 g/ml underestimated the anatomic LVM by 18.1% (p < 0.0001). CONCLUSION: PMCT is a helpful tool for the assessment of LVM, and LVShV is highly correlated with LVM as assessed by subsequent autopsy. The correlation between the two was independent of gender, hypertrophy and LV asymmetric hypertrophy. We found a higher myocardial tissue density of 1.265 g/ml compared to previous studies. We show that PMCT combined with autopsy may contribute not only to anatomical but also clinical knowledge.

Post-mortem computed tomography as part of dental identification - a proposed guideline.

PURPOSE: This paper presents a proposed guideline for the use of post-mortem computed tomography (PMCT) during forensic dental identification. Currently, whole-body PMCT is widely used prior to autopsies for the diagnosis of fractures, organ changes, hemorrhages, and for the localization of foreign bodies, but it may also facilitate the odontological identification process in single cases and in cases involving multiple fatalities. Several studies have described the use of PMCT in forensic odontological work, but we have not found any comprehensive set of guidelines on how to perform a forensic odontological examination using PMCT. The aim was to develop guidelines for creating post-mortem dental charts during forensic odontological identification examinations using the standard functions of PMCT. METHODS: A proposed guideline was developed from 15 selected cases examined at the Section of Forensic Pathology, Department of Forensic Medicine at the University of Copenhagen in Denmark from October 2011 to May 2012. Using the functionalities and three-dimensional (3D) reconstructions of OsiriX DICOM-viewer software (Pixmeo Sarl, Bernex, Geneva, Switzerland) we adjusted the contrast and brightness settings and developed a proposed guideline for creating PMCT-based dental charts. A four-step guideline was produced. CONCLUSION: In our casework, we are currently using the guidelines proposed herein. The use of PMCT has allowed us to target our clinical examinations, greatly improving their efficiency. Furthermore, PMCT allows the storage of data for later documentation and research. Further research is needed to validate the proposed guideline.

The accessory magnocellular neurosecretory system of the rostral human hypothalamus.

The morphology and neurophysin expression of the magnocellular accessory neuroendocrine system located in the rostral human hypothalamus is investigated in a series of brains obtained at autopsy. The hypothalami were fixed in formalin and embedded in paraffin, or after cryoprotection, frozen for cryostat sectioning. Paraffin sections were either stained with Luxol Fast blue or immunoreacted for neurophysin I or neurophysin II, the precursor molecule for oxytocin and vasopressin. Further, 50-µm-thick serial cryostat sections were immunoreacted with the same antibodies. Both the paraventricular and supraoptic nuclei as well as the hypothalamo-hypophysial tracts exhibited strong immunoreactivity for the neurophysin antibodies. In addition, large collections of immunoreactive accessory magnocellular nuclei and single scattered neurophysin-positive neurons were located in the preoptic region between the paraventricular and supraoptic nucleus among the hypothalamo-hypophysial nerve fibers. In addition, smaller collections of neurophysin-immunoreactive neurons were located in the basal part of this region. Among the accessory magnocellular nuclei, the classical circular nucleus was identified. Accessory magnocellular neurons were often located along the blood vessels and projections of some of these neurons penetrated the vascular endothelium. The accessory magnocellular cell bodies expressed either neurophysin I or neurophysin II immunoreactivity. Summarizing, the accessory magnocellular system in the human brain is large and differs in morphology compared to the system seen in other vertebrates. The neurons of this system contain both vasopressin and oxytocin. Some neurons of the accessory neuronal systems might secrete vasopressin or oxytocin directly into the blood stream.

Epicardial adipose tissue volume estimation by postmortem computed tomography of eviscerated hearts.

Epicardial adipose tissue (EAT) may play a role in the development of coronary artery disease. The purpose of this study was to evaluate a method based on postmortem computed tomography (PMCT) for the estimation of EAT volume. We PMCT-scanned the eviscerated hearts of 144 deceased individuals, who underwent a medicolegal autopsy. Using Mimics® we performed segmentation of the images and obtained the volumes of EAT and myocardium. Total heart volume was calculated by adding the volumes of EAT and myocardium. Total heart weight, including EAT, myocardium and attached vessels, was measured during autopsy. Inter-observer analysis was performed on 30 randomly chosen subjects. We included 132 individuals in the results (age range: 22-94 years; 56% men). Twelve individuals were excluded due to inadequate PMCT scanning. Median EAT volume was 73.0 mL (Interquartile range; IQR: 45.6-113.7 mL) in men and 64.8 mL (IQR: 44.0-98.0 mL) in women, which accounted for 20.4 ± 10.2% and 21.9 ± 9.5% of total heart volume, respectively. This corresponded with former autopsy studies. Total heart volume measured by PMCT was highly correlated with heart weight (R2 = 90%). Mean inter-observer difference of EAT volume was -1.7 mL (95% limits of agreement: -37.0-33.6 mL), with an Intra Class Correlation of 0.91. It was possible to estimate EAT volume using PMCT on eviscerated human hearts. Our method was fast and accurate with good inter-observer agreement. This is a useful method to determine EAT at autopsy, and we will apply this method in future research.

Obtaining appropriate interval estimates for age when multiple indicators are used: evaluation of an ad-hoc procedure.

When an estimate of age is needed, typically multiple indicators are present as found in skeletal or dental information. There exists a vast literature on approaches to estimate age from such multivariate data. Application of Bayes' rule has been proposed to overcome drawbacks of classical regression models but becomes less trivial as soon as the number of indicators increases. Each of the age indicators can lead to a different point estimate ("the most plausible value for age") and a prediction interval ("the range of possible values"). The major challenge in the combination of multiple indicators is not the calculation of a combined point estimate for age but the construction of an appropriate prediction interval. Ignoring the correlation between the age indicators results in intervals being too small. Boldsen et al. (2002) presented an ad-hoc procedure to construct an approximate confidence interval without the need to model the multivariate correlation structure between the indicators. The aim of the present paper is to bring under attention this pragmatic approach and to evaluate its performance in a practical setting. This is all the more needed since recent publications ignore the need for interval estimation. To illustrate and evaluate the method, Köhler et al. (1995) third molar scores are used to estimate the age in a dataset of 3200 male subjects in the juvenile age range.

A method for estimating age of medieval sub-adults from infancy to adulthood based on long bone length.

OBJECTIVES: To develop a series of regression equations for estimating age from length of long bones for archaeological sub-adults when aging from dental development cannot be performed. Further, to compare derived ages when using these regression equations, and two other methods. MATERIAL AND METHODS: A total of 183 skeletal sub-adults from the Danish medieval period, were aged from radiographic images. Linear regression formulae were then produced for individual bones. Age was then estimated from the femur length using three different methods: equations developed in this study, data based on a modern population (Maresh: Human growth and development (1970) pp 155-200), and, lastly, based on archeological data with known ages (Rissech et al.: Forensic Sci Int 180 (2008) 1-9). As growth of long bones is known to be non-linear it was tested if the regression model could be improved by applying a quadratic model. RESULTS: Comparison between estimated ages revealed that the modern data result in lower estimated ages when compared to the Danish regression equations. The estimated ages using the Danish regression equations and the regression equations developed by Rissech et al. (Forensic Sci Int 180 (2007) 1-9) were very similar, if not identical. This indicates that the growth between the two archaeological populations is not that dissimilar. DISCUSSION: This would suggest that the regression equations developed in this study may potentially be applied to archaeological material outside Denmark as well as later than the medieval period, although this would require further testing. The quadratic equations are suggested to yield more accurate ages then using simply linear regression equations.

Archaeological, radiological, and biological evidence offer insight into Inca child sacrifice.

Examination of three frozen bodies, a 13-y-old girl and a girl and boy aged 4 to 5 y, separately entombed near the Andean summit of Volcán Llullaillaco, Argentina, sheds new light on human sacrifice as a central part of the Imperial Inca capacocha rite, described by chroniclers writing after the Spanish conquest. The high-resolution diachronic data presented here, obtained directly from scalp hair, implies escalating coca and alcohol ingestion in the lead-up to death. These data, combined with archaeological and radiological evidence, deepen our understanding of the circumstances and context of final placement on the mountain top. We argue that the individuals were treated differently according to their age, status, and ritual role. Finally, we relate our findings to questions of consent, coercion, and/or compliance, and the controversial issues of ideological justification and strategies of social control and political legitimation pursued by the expansionist Inca state before European contact.