The Power of Exclusion using Automated Osteometric Sorting: Pair‐Matching,

This study compares the original pair‐matching osteometric sorting model (J Forensic Sci 2003 ;48:717) against two new models providing validation and performance testing across three samples. The samples include the Forensic Data Bank, USS Oklahoma, and the osteometric sorting reference used within the Defense POW/MIA Accounting Agency. A computer science solution to generating dynamic statistical models across a commingled assemblage is presented. The issue of normality is investigated showing the relative robustness against non‐normality and a data transformation to control for normality. A case study is provided showing the relative exclusion power of all three models from an active commingled case within the Defense POW/MIA Accounting Agency. In total, 14,357,220 osteometric t‐tests were conducted. The results indicate that osteometric sorting performs as expected despite reference samples deviating from normality. The two new models outperform the original, and one of those is recommended to supersede the original for future osteometric sorting work.     

An Analysis on the Choice of Alpha Level in the Osteometric Pair‐matching of the Os Coxa,Scapula, and Clavicle

This study compares the use of 0.05 and 0.10 alpha levels with the updated osteometric pair‐matching model on two samples of the os coxa, scapula, and clavicle. The samples include the Forensic Data Bank, and the osteometric sorting reference used within the Defense POW/MIA Accounting Agency. Mixed‐effects two‐way analyses of variance were used to analyze bilateral asymmetry in the standard measurements. In total, 3,793,566 t‐tests were conducted for osteometric pair‐matching analysis. The results indicate high levels of exclusion power, and accuracy can be obtained with the os coxa and scapula. The clavicle standard measurements capture too much asymmetry causing a lower exclusion to accuracy ratio for osteometric pair‐matching relative to other elements. Both 0.05 and 0.10 alpha levels provide acceptable levels of performance. A lower alpha level will result in higher accuracy with less exclusion, and a higher alpha level will result in lower accuracy with more exclusions.     

Osteometric sorting of commingled human remains

This paper describes the method of osteometric sorting. Osteometric sorting is the formal use of size and shape to sort bones from one another. The method relies heavily on measurement data and statistical models and is designed to maximize objectivity. The goal of this paper is to validate the use of osteometric sorting and to provide case examples of its utility. Selected regression models are also presented for use with osteometric sorting. We advocate this technique as one tool among many in the anthropologist's toolkit for sorting commingled skeletal remains.     

Tables for the Metric Evaluation of Pair‐Matching of Human Skeletal Elements

A common task in forensic anthropology involves pair‐matching of left and right skeletal elements. This can be achieved through visual pair‐matching by evaluating similarities in morphology, and through osteometric sorting, a quantitative technique. To simplify the process of osteometric sorting, this article explains the use of a statistic (M), which captures the amount of size variation found between homologous bones from single individuals. A database of skeletal measurements for all major paired postcranial bones is used to calculate values of M from a variety of sources. The maximum value and the 90th and 95th percentiles of M are provided in tabular format, and values of M from forensic cases can be compared to these tables as an objective means for determining whether homologous bones could have originated from the same individual. This simple technique can be combined with visual pair‐matching to be particularly effective in cases involving commingling of skeletons.     

Anthropological Measurement of the Juvenile Clavicle Using Multi‐Detector Computed Tomography—Affirming Reliability

Currently, there is no standardized protocol for multi‐detector computed tomography (MDCT) measurement of juvenile remains. Using 33 juvenile clavicles, this paper investigates a protocol to allow MDCT measurements, comparable or supplemental with traditional osteometric measurements, to be acquired for application to previously published algorithms. The results illustrate that there is no significant difference between MDCT measurements and those taken by direct osteometric methods. By presenting such a protocol, this paper takes the first steps toward validation of the process of conversion from measurement of dry juvenile bone to MDCT compatibility and allows the forensic world to take a step forward in standardizing the way MDCT is used for forensic practice. This paper assesses the limitations and potential applications of this virtual approach and offers some suggestions for where further work might progress the conversion of these new approaches into legally admissible anthropological techniques of age estimation.     

Z‐Transform Method for Pairwise Osteometric Pair‐matching,

A new pairwise osteometric pair‐matching approach based on the Z‐transform method is presented. In contrast to previous methods that perform a global t‐test on the summed skeletal element pair measurement distances, this approach performs t‐tests on each individual distance, facilitating the capture of measurement‐specific variation. This new approach is compared to published pairwise sorting methods using a standard reference dataset of postcranial remains maintained by the Defense POW/MIA Accounting Agency. Receiver operating characteristic curve analysis indicates significantly improved performance for the clavicle and radius over all previous methods (p < 0.01). The z‐transform method weighted by the effect size outperformed the t‐test (Byrd and Adams) and the mean t‐test (Lynch) for all elements (p < 0.01). The method performed better than the absolute value t‐test (Lynch) for five elements (p < 0.01) and performed at least as well for the remainder. To facilitate usability all methods are available at: https://github.com/spawaskar-cora/z-transform-method .     

Testing the validity of population-specific sex estimation equations: An evaluation based on talus and patella measurements

Sex estimation is essential for forensic scientists to identify human skeletal remains. However, the most sexually dimorphic elements like pelvis or skull are not always assessable. Osteometric analyses have proven useful in sex estimation, but also to be population specific. The main purpose of this study was to test the validity of contemporary Greek and Spanish discriminant functions for the talus and the patella, respectively, on a Swiss skeletal sample and to quantify the utility of the measurements as a novel approach in osteometric sex assessment.Four talus and three patella measurements on dry bone were obtained from 234 individuals of the modern cemetery SIMON Identified Skeletal Collection. The previously derived discriminant functions were applied, accuracies determined, the utility of the different measurements was assessed and new multivariable equations constructed.Accuracies varied between 67% and 86% for talus and 63% and 84% for patella, similar to those reported by the original studies. Multivariable equations should be preferred over equations based on single measurements and combining the most significant measurements rather than using several variables obtained the best possible accuracy. The new discriminant functions did not provide a substantial improvement to the original ones. The overall utility of talus and patella is limited, allowing sex estimation with sufficient certainty only in a small proportion of individuals.Discriminant functions developed in contemporary Greek or Spanish populations are in principle applicable also to Swiss contemporary populations. We recommend that at present existent studies of this type should be validated and tested rather than developing new formulas.     

Advances in Osteometric Sorting: Utilizing Diaphyseal CSG Properties for Lower Limb Skeletal Pair-Matching

Pair-matching of bilateral elements is a major component of resolving commingled remains both in forensic and bioarchaeological contexts. This study presents a new method of osteometric pair-matching of the lower limbs which relies on 3D digital models of the femur and tibia bones. The proposed method, which is accompanied by a freely available open-source implementation, automatically computes a number of osteometric variables including cross-sectional geometric properties from an assemblage of left and right bone antimeres and calculates probabilistically the appropriate matching pairs as well as single elements, whose bones antimere is not present in the given assemblage. The method has been extensively tested on a skeletal sample comprising 396 femurs and 422 tibias from the Athens collection. Our results in testing commingled assemblages with no disparity show that the method’s sensitivity is 1 for sorting femurs and 0.997 for sorting tibias, whereas in assemblages with moderate disparity the sensitivity is 0.999 and 0.992 respectively. Our results further indicate that sensitivity is unaffected by the size of the commingled assemblage although the percentage of identified true matching pairs drops as the number of commingled elements increases. This means that all identified antimeres matched to an individual are still very accurately sorted despite not every individual being identified in very large assemblages. The proposed method can facilitate the sorting process of commingled remains both accurately and efficiently, while leaving a very small percentage of unsorted elements that may require further techniques for further individualization.     

Osteometric variation in the humerus: sexual dimorphism in South Africans

There has been a surge of research on forensic anthropology in South Africa. Differences between the populations of this country and others are demonstrated in many studies. Yet, many forensic osteometric techniques based on other populations are still in use. The purpose of the present study is to develop an osteometric sex determination technique using the humerus. The sample is composed of skeletons of 104 whites and 88 blacks from the Dart and Pretoria collections. Six humeral dimensions were initially analyzed using stepwise discriminant function statistics. Humeral head diameter, deltoid tuberosity circumference and epicondylar breadth were individually calculated in order to make the technique usable for fragmented remains. The results indicated that the head and epicondylar diameters are the best in whites to differentiate sexes from each other, while head diameter and maximum length are best in blacks. Accuracy of correct classification was as high as 96% in whites and 95% in blacks. Crossvalidation provided the same accuracy as the original classification. These accuracy percentages are as high as those expected from the femur and tibia. Posterior probability, which measures the percent affiliation of the sample with its original sex group, was also mostly 80% or better. South African collections are ideal for osteometric analysis, because they are still growing in numbers with cross-sectional representatives from the country.     

Sexual Dimorphism of the Humerus in Contemporary Cretans—A Population‐Specific Study and a Review of the Literature*

Abstract: Sex determination is the first essential step for positive identification when a decomposed body is recovered. Taking into consideration the population aspect of sexual dimorphism of the skeleton, the present study aimed to create a sex identification technique using osteometric standards, derived from a contemporary Cretan population. A total of 168 left humeri were measured according to standard osteometric techniques. The differences between the means in males and females were significant (p < 0.0005). About 92.3% of cases were correctly classified when all measurements were applied jointly. Stepwise procedure produced an accuracy rate of 92.9%. The most effective single dimension was vertical head diameter (89.9%). The current study provides standards for a population that has not been represented so far in the existing databases. It demonstrates that the humerus is an effective bone for the estimation of sex because even in a fragmentary state it can give high classification accuracy.     

How “Standardized” is Standardized? A Validation of Postcranial Landmark Locations

Since the mid‐1990s, osteometrics have been a major aspect in forensic anthropology. However, recent evidence has shown that practitioners have been using differing points to establish certain measurements; namely those involving the clavicle, scapula, ulna, femur, and tibia. Engaging 61 practitioners, this study examined and confirmed how extensive this discord is. The highest consistency rate among practitioners was the scapular breadth (62.3%), followed by the femoral anteroposterior subtrochanteric diameter (55%). All other levels fell below these, particularly the physiological length of the ulna which was the most inconsistently measured bone. Furthermore, these low consistency rates yielded percent mean differences between two and 20% of the measurement length, with ranges averaging 14 mm. In light of these results, it is recommended that the field take steps to improve the standardization of such problematic measurements, including reexamining all measurements currently listed in osteometric texts, reassessing the utility of each, and reissuing a comprehensive guide.     

Craniometric analysis of the modern Cretan population

Despite the fact that sex assessment using craniofacial characteristics is commonly made worldwide, a lack of such investigation is noted in the Balkan area and in Greece in particular. The aim of this study is to develop a sex determination technique using osteometric data from skeletal remains of a contemporary Cretan cemetery population.A total of 90 males and 88 females are measured according to standard osteometric techniques. Age differences are not significant (mean age for men = 68.94 ± 13.41, N = 66; for women = 73.21 ± 16.77, N = 66). A total of 16 dimensions taken from the craniofacial skeleton are used and data are analyzed using SPSS subroutines. A comparison is made with other contemporary populations, including Americans (Terry collection) and South Africans (Dart and Pretoria collections), as well as an archaeological sample (Middle and Late Helladic) from Crete.Results indicate that males are statistically significantly greater than females in all dimensions. Bizygomatic breadth is the most discriminatory single dimension and can provide an accuracy rate of 82% on average. Using a stepwise method involving five dimensions (bizygomatic breadth, cranial length, nasion–prosthion and mastoid height and nasal breadth), accuracy is raised to 88.2%. Interestingly, cranial length is selected as the first discriminating variable by the stepwise analysis when only the neurocranium is available for measurement.     

Analysis of Three Commonly Used Tibia Length Measurement Techniques

This study analyzes three tibia length measurement techniques on a sample of 107 tibiae. Two of the techniques meet published criteria by resting the tibia on its posterior surface with the longitudinal axis parallel to an osteometric board. The third technique does not adequately keep the longitudinal axis parallel to the board. Statistical analyses show low levels of interobserver error for all techniques and statistically significant differences between the third technique and the other two techniques. Results report a maximum difference of 6 mm between measurement techniques with the third technique having greater than 95% directional bias. A survey sent out to the American Academy of Forensic Sciences forensic anthropology community reported more than 50% of respondents having been taught the third technique when an osteometric board with a slot/hole is not available. The intermixing of the third technique with the other two has likely contributed to higher levels of interobserver error in tibia length measurements.     

Veldt fires in South Africa: Implications on osteometry and the biological profile

Standard operating procedures for forensic anthropological analyses dictate that thermally altered remains should not be measured, hindering the creation of a biological profile. Few studies have addressed estimating biological parameters from burned remains, with the greatest focus of this research area being on cremated remains. However, veldt fires are more common than cremation in the South African forensic context. The aim of this study was to explore the degree of structural changes observed in domestic pig (Sus scrofa) bones associated with thermal destruction and the potential impact on the estimation of a biological profile using standard osteometric methods. A total of 96 pig femora were divided equally into two categories: fresh and dry. Within each category, equal samples were exposed to different durations of burning, namely, 5, 10, and 20 min. Ten standard femoral anthropological measurements were collected before and after burning. Technical error of measurement and Wilcoxon signed-rank tests were used to assess changes in the femoral dimensions before and after burning. Most measurements were significantly different after burning, with the fresh bones decreasing in size by up to 7.8% and the dry bones decreasing in size by up to 4.0%. The magnitude of post-burning measurement changes for both burn conditions was similar to, or smaller than has previously been reported for observer measurement errors of commonly used variables investigated for standard osteometric studies. Veldt fires are less intense than cremation, thus causing less shrinkage.     

Criteria of personal identification by the hyoid bone

We studied 16 sizes of the hyoid bone (HB) from 158 corpses of known gender, Russians, who had died at the age over 15 years by the K. Miller et al program (1998) and 205 back projection electroroentgenograms of the neck of patients of the traumatological hospital in the town of Kirov. HB skeletization was made by the enzymatic drug enzyme. SPSS package and multidimentional statistics (regression and discriminant analyses) were used for data processing. It was established that HB is an informative object of forensic medical personal identification allowing determination of the body length and gender as well as anatomical, x-ray and osteometric individual features. Precision of human body length diagnosis by HB is 6.71-7.26 cm. Therefore, this method should be used in combination with the diagnosis by long tubular bones. Diagnosis of human gender by osteometric signs of HB based on one-dimentional discriminant analysis is feasible in 80-85%, based on canonical discriminant analysis--in 91.1% cases. The method of anatomic, osteometric and roentgenological assessment of HB individuality can be used in personal identification by intravital x-ray of cervical organs and in traumatic defects of HB. The methods may be applied in forensic medical practice in expert examination of body fragments or isolated bone fragments.     

Long Bone (Humerus,Femur, Tibia) Measuring Procedure in Cadavers

In this work, we present a measuring methodology for long bones of the limbs (humerus, femur, and tibia) of human corpses. Measurements of cadaveric height and long bone lengths were conducted on 72 corpses (20 females and 52 males) from the School of Medicine at the National Autonomous University of Mexico. Additionally, these measurements were compared with those taken from dry bones of a subsample of individuals. Our results show marginal differences (TEM% = 0.59) between cadaveric and dry bone measurements, resulting from different osteometric technical procedures. This note outlines the measuring methodology, which will be subsequently used to create regression formulas for stature estimation.     

Forensic Dental Age Estimation by Measuring Root Dentin Translucency Area Using a New Digital Technique

Dentin translucency measurement is an easy yet relatively accurate approach to postmortem age estimation. Translucency area represents a two‐dimensional change and may reflect age variations better than length. Manually measuring area is challenging and this paper proposes a new digital method using commercially available computer hardware and software. Area and length were measured on 100 tooth sections (age range, 19–82 years) of 250 μm thickness. Regression analysis revealed lower standard error of estimate and higher correlation with age for length than for area (R = 0.62 vs. 0.60). However, test of regression formulae on a control sample (n = 33, 21–85 years) showed smaller mean absolute difference (8.3 vs. 8.8 years) and greater frequency of smaller errors (73% vs. 67% age estimates ≤ ±10 years) for area than for length. These suggest that digital area measurements of root translucency may be used as an alternative to length in forensic age estimation.     

Improving Luminol Blood Detection in Forensics

The aim of this study was to develop chemical improvements to the original Weber protocol, in order to increase the intensity and time length of light emission and to eliminate false‐positive reactions. The intensity and duration of light were measured on serial blood dilutions using a plate reader chemiluminometer. Blood stains of various concentrations were impregnated in pure cellulose, dried, and luminol solution was added with/without the potential enhancers. An in silico study was also conducted, aiming to demonstrate the enhancing mechanism of hemoglobin denaturation using 8 M urea. The luminol blood detection test revealed important improvements after urea pretreatment or in the presence of monochloro‐triazinyl‐β‐cyclodextrin. This approach also eliminated the false‐positive reaction from sodium hypochlorite. These improvements could provide a higher sensitivity under particular circumstances such as old or washed blood stains, leading to a better localization for further DNA typing and higher quality photographic analysis.     

A Reliable Regression‐Based Approach for Reassociating Human Skeletal Elements of the Lower Limbs from Commingled Assemblages

Accurate sorting of commingled human remains comprises a fundamental requirement for all further anthropological analyses. The lower limb bones are particularly important for reconstructing biological profiles. This study introduces a metric technique for sorting these elements using eight standard anthropological measurements and 222 adult individuals from Greece. The bones utilized were the os coxae, the femora, the tibiae and the tali. Simple regression analyses were used to develop functions for reassociating articulating bones, providing strong correlations (r = 0.74–0.95, p‐value <0.05) and high coefficients of determination (r²=0.54–0.91). Blind tests demonstrated that combining metric and morphoscopic techniques provides an excellent sorting accuracy for the hip and knee joints (ten of ten individuals), allowing for a reliable reassociation between a sex and age indicator (os coxae) and a body size indicator (femur). Overall, these results indicate the high value of metric methods in sorting commingled human remains.     

Forearm bones and sexual variation in Turkish population

Forensic anthropologists are aware that there are considerable differences between human populations and therefore develop study models for each skeletal population. The purpose of this study was to analyze forearm bones obtained from forensic settings in Turkey. The sample consists of 42 males and 38 females with an average age of 40 and 36 years, respectively. Numerous measurements were taken from the radius and ulna including lengths (in millimeters), midshaft diameters, and epiphyseal breadths (0.01 mm). Individuals with any anomaly and pathology were not included in the investigation. A stepwise analysis, when applied to individual bones, selected only length and midshaft transverse dimension in the radius and length only in the ulna. When the length was excluded from the statistic, head diameter and distal breadth of the radius and distal minimum head and midshaft anteroposterior diameters of the ulna provided the best predicting functions. Classification results were 92% for the radius and 91% for the ulna. For the incomplete bones, the accuracy rates were about 92% and 83%, respectively. In conclusion, a sex determination was made, in different rates of accuracy, in the human skeleton. Correct assessment can vary among populations. Dimorphism in our region forearm bones is greater than American whites. This supported the hypothesis that human variation is diverse, and population difference should be taken into account when osteometric standards are applied to others. Further studies are needed to understand why the forearm is more dimorphic in Turks.