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.     

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.     

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.     

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 .     

Sexual dimorphism of the scapula and the clavicle in a contemporary Greek population: applications in forensic identification

Sex estimation is the grounds for an accurate identification of unknown human skeletal elements. The need for reliable methods distinguishing males from females based upon various skeletal elements is evident in cases of commingled, eroded and/or missing remains. The aim of this work lays on establishing criteria for sex estimation from the scapula and the clavicle in modern Greeks. A total of 147 left scapulae and 147 clavicles (66 females and 81 males) were used in the study. Eight and six measurements were taken on the scapula and clavicle respectively and data were subjected to principal components analysis (PCA) and discriminant function analysis (DFA). Posterior probabilities for the classification of each individual are also calculated. Statistical analysis was carried out using the software PAST (Paleontological Statistics) and SPSS (Statistical Package for Social Sciences) 18. The results supported the existence of pronounced sexual dimorphism, which was mainly attributed to size differences among the two groups. Univariate and multivariate methods of statistical classification showed high accuracy for all scapular and most clavicular measurements, verifying their value as sex indicators in the under study population. We recommend the use of this method for sex assessment from the scapula and the clavicle in cases exhibiting over 95% probability of correct classification. This is regardless of the overall high degree of accuracy reported here, as the method of choice in forensic contexts should always be case-driven.     

Determination of sex from the clavicle and scapula in a Guatemalan contemporary rural indigenous population

The clavicle has been described as a useful bone for the metric determination of sex of human skeletal remains in a contemporary, predominantly white, North American forensic sample. In this article, measurements of clavicle and scapula are provided for a contemporary Guatemalan rural indigenous sample of forensic origin. Maximum length and circumference at midshaft of the clavicle, and height and width of the glenoid fossa of the scapula, were measured in 35 female and 62 male clavicles, and in 38 female and 65 male scapulae. Discriminant function analysis was used to study sexual dimorphism in this population with a classification purpose. Leave-one-out method (jackknife) matrices produced classification success rates ranging from 85.6% to 94.8%. A comparison with the North American forensic sample showed low percentages of correctly sexed Guatemalan male clavicles, ranging from 29.4% to 54.9%. The choice of an appropriate standard for the metric determination of sex is a crucial step in forensic anthropology.     

The Automation of Regression Modeling in Osteometric Sorting: An Ordination Approach

This study compares the original osteometric sorting association method with an ordination approach across all combinations of the humerus, ulna, radius, femur, tibia, and fibula. This includes both the original prediction interval and t‐statistic approaches. Standard measurements are utilized in the models with full measurements combined and without length measurements. The sample is the osteometric sorting reference from the Defense POW/MIA Accounting Agency. A full set of performance statistics is provided. Results indicate the ordination approach outperforms the original in the majority of bone combinations. Models with length measurements have more exclusion power than those without. It is recommended for the ordination approach to supersede the original when applied to large commingled assemblages.     

Bilateral Asymmetry of Nutrient Foramen Position in Forearm Bones: Implications for its Use in Sorting Commingled Remains

Commingling is frequently encountered in cases examined by the Committee on Missing Persons in Cyprus, and pair‐matching is routinely used as a preliminary segregation method. Here we examine the degree of bilateral asymmetry in nutrient foramen position of the radius and ulna to determine whether nutrient foramen position may be useful in visual and/or ostetometric pair‐matching. Differences in nutrient foramen position between left‐right pairs from the same individual were compared with differences in nutrient foramen position between different individuals. Bilateral asymmetry in nutrient foramen position was found to be high, indicating that it is not a reliable trait for pair‐matching. Bilateral asymmetry and between‐person variation were found to differ between the two bones examined, suggesting that nutrient foramen position in other long bones should also be tested.     

Multimethod Resolution of a Small‐Scale Case of Commingling

This study highlights the use of multiple methods for resolving a case of commingled human remains. Skeletal remains were located in a marijuana field in rural northern California by law enforcement. Although initially buried in shallow graves, the remains of two decedents were disturbed by large carnivores and scattered over a wide area. The remains were submitted by law enforcement for forensic anthropological analysis and resolution of commingling. To segregate the remains of the two individuals, a number of methods were employed, including: (i) physical matching of fragmented remains; (ii) articulation to evaluate joint congruence; (iii) visual pair‐matching of bilateral elements; (iv) osteometric pair‐matching; (v) evaluation of taphonomic patterns; (vi) DNA analysis; and (vii) portable X‐ray spectrometry (pXRF). This multimethod approach resulted in accurate resolution of the commingling and facilitated reconstruction of the biological profiles, taphonomic patterns, and trauma analysis for each individual.     

A New Method to Pair‐match Metacarpals Using Bilateral Asymmetry and Shape Analysis

Matching pairs of skeletal elements is of fundamental importance when re‐associating skeletons from commingled settings. This study presents a new method that combines the use of traditional anthropometric size measurements and the analysis of shape, through geometric morphometrics, to form pairs from commingled settings. We tested the hypothesis that shape asymmetry among individuals is smaller than between individuals that share similar dimensions. The metacarpals were measured in their maximum length, and absolute means of asymmetry between right and left metacarpals were calculated. To analyze the shape characteristics, two‐dimensional landmarks were recorded from digital images of 111 metacarpals. The specimens were analyzed using generalized Procrustes analysis and multivariate statistics. The accuracy of pair‐matching bones using a combined method was of 100%, showing that the incorporation of geometric morphometrics techniques—in the assessment of shape in physical anthropology—is of particular use when comparing the shape differences/similarities between individuals.     

Proposed Method for Predicting Pair Matching of Skeletal Elements Allows Too Many False Rejections

Byrd proposes a method for predicting pair matches in commingled remains to reduce visual comparison. The method compares differences between left and right postcranial element measurements in commingled samples with differences in known pairs from a reference sample using a t‐score approach. We duplicated his protocol using six elements from two samples of known paired elements (n = 854 to 1063) and calculated the number of pairs correctly predicted. Time commitment was estimated by mathematically attempting matches with all left and right elements in these samples. Although the results show an 86% reduction in the number of potential pairs requiring visual matching, we do not recommend the method because (i) the normality assumption for use of a t‐score approach is violated, (ii) no account is made for bilateral asymmetry, and (iii) the high rate of false rejections (up to 22%) undermines its ability to show true incompatibilities for potential pair matches.     

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.     

The Use of Entheseal Changes in the Femur and Os Coxa for Age Assessment

This study examined the relationship between age and entheseal modifications in the femur and os coxa for estimating age at death. Five areas on the os coxa and four on the femur were scored in 200 white individuals over 40 years of age. Statistical analyses assessed the relationship between age and entheseal modification using both raw scores and scores adjusted for body size, for each sex, and for sexes combined. Results indicate that significant relationships exist between age and entheseal modification at three sites on the femur and four on the os coxae, but the relationships are not strong enough to generate age predictions. Conversely, the most severe entheseal modifications show promise as an indicator of age in older adults. Although further research is needed using larger samples for robust statistical analyses, current data indicate these modifications can suggest an age >60, or in some cases 70, years.     

A Method for Estimating Sex Using Metric Analysis of the Scapula*

Abstract: The most accurate and precise methods for the assessment of age and stature often require knowledge of sex. Thus, being able to correctly identify sex from skeletal remains is critical in the forensic context. The presence of the os coxae or skull can never be guaranteed, making the development of reliable methods of sex estimation using other skeletal elements necessary. Using a 724 individual calibration sample from the Hamann‐Todd collection, this study identifies sexual dimorphism in the human scapula, and presents a new five‐variable discriminant function for sex estimation. The overall accuracy of this method proved to be 95.7% on the cross‐validated calibration sample, 92.5% on an 80 individual test sample from the Hamann‐Todd collection, and 84.4% on a 32 individual test sample from the skeletal collection of the Wichita State University Biological Anthropology Laboratory. Additionally, a slightly less accurate two‐variable model was developed and has cross‐validated accuracy of 91.3%.     

An evaluation of determination of handedness using standard osteological measurements

Numerous studies have assessed side dominance assuming arm bones on the side of handedness will be larger, but concerns over sample size or replicability of measurements usually emerged. Attempting to improve upon these limitations, this investigation analyzes patterns of side difference for standard length and transverse dimensions of the scapula, clavicle, humerus, ulna, and radius for 137 individuals of known handedness. The results showed that with few exceptions, the right side of the skeleton was consistently larger in most individuals regardless of side dominance. Combinations of other measurements previously suggested to be indicative of handedness as well as the use of discriminant analysis also failed to provide reliable estimators. These findings are likely related to the fact that activities of modern individuals are generally not sufficiently unilateral in their stresses to cause asymmetrical development in the arm bones. Therefore, it is recommended that other means be developed to assess side dominance.     

中国汉族男性肩胛骨测量值与身长的关系

目的　探讨中国汉族男性肩胛骨测量值与身长的关系。方法　测量了 2 0 7例已知身长的中国汉族男性肩胛骨的 14项指标 ,用测得的数据输入计算机 ,分 3个年龄段 ,运用多元线性回归分析法 ,求出肩胛骨测量值推算身长的方程式。结果　建立了用男性肩胛骨推算身长的 9个方程式 ,其复相关系数在 0 65 99至 0 5 192之间 ,标准差在 5 13 45至 6 3 93 1之间。结论　中国汉族男性肩胛骨测量值与身长呈现一定的相关关系。     

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.     

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.     

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.