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Papers by Daniel Franklin

Australian Journal of Forensic Sciences, 2019

The histological analysis of bone for forensic application requires thin sections to be prepared ... more The histological analysis of bone for forensic application requires thin sections to be prepared from extracted bone of suitable quality for visualization through conventional light microscopy and (if required) the measurement of microstruc-tural features, such as osteons. While a number of protocols for the preparation of thin sections exist, they are often time consuming and complex, or require expensive and non-portable equipment. A revised protocol is presented for obtaining high quality thin sections for light microscopy and histological analyses , tested in fresh, fixed, and dry archaeological cortical bone. It does not require extensive experience, or expensive materials or equipment, and can be further adapted for use with manual tools if necessary.

British Journal of Midwifery, 2015

ABSTRACT

Forensic Science International, 2015

Age estimation in the juvenile skeleton primarily relies on the assessment of the degree of denta... more Age estimation in the juvenile skeleton primarily relies on the assessment of the degree of dental and skeletal development relative to full maturity. The timing of the mineralization and eruption of the teeth is a sequential process that, compared to skeletal growth and development, is less affected by extrinsic influences such as nutrition and/or chronic illness. Accordingly, radiographic visualization and analysis of different tooth formation stages are the foundation for a number of widely applied age estimation standards. Presently, however, there is a relative paucity of contemporary dental age estimation standards for a Western Australian population. To that end, the aim of the present study is to develop statistically quantified radiographic age estimation standards for a Western Australian juvenile population. A total of 392 digital orthopantomograms (202 male and 190 female) of Western Australian individuals are analyzed. Following, Moorrees et al. (J. Dent. Res. 42 (1963a) 490-502; Am. J. Phys. Anthropol. 21 (1963) 205-213), dental development and root resorption was assessed. Alveolar eruption was analyzed following Bengston (Northwest Univ. Bull. 35 (1935) 3-9). Stages of dental development were used to formulate a series of age estimation polynomial regression models; prediction accuracy (±0.998 to 2.183 years) is further validated using a cross-validation (holdout) sample of 30 film orthopantomograms. A visual atlas of dental development and eruption was subsequently designed for the pooled sex sample. The standards presented here represent a non-invasive and statistically quantified approach for accurate dental age estimation in Western Australian juvenile individuals.

International journal of legal medicine, Jan 15, 2014

The clavicle is the first bone to ossify in the developing embryo and the last to complete epiphy... more The clavicle is the first bone to ossify in the developing embryo and the last to complete epiphyseal union. It is the latter sustained period of growth that has attracted the interest of skeletal biologists and forensic practitioners alike, who collectively recognize the important opportunity this bone affords to estimate skeletal age across the prenatal to early adult lifespan. Current research is largely directed towards evaluating the applicability of assessing fusion in the medial epiphysis, specifically for determining age of majority in the living. This study aims to contribute further insights, and inform medicolegal practice, by evaluating the Schmeling five-stage system for the assessment of clavicular development in a Western Australian population. We retrospectively evaluated high-resolution multiple detector computed tomography (MDCT) scans of 388 individuals (210 male; 178 female) between 10 and 35 years of age. Scans are viewed in axial and multiplanar reconstructed (...

Forensic Science International, 2014

The forensic anthropologist is responsible for contributing to the identification of an unknown b... more The forensic anthropologist is responsible for contributing to the identification of an unknown by constructing a biological profile from their skeletal remains. Towards achieving this goal, anthropologists can apply population and temporally specific standards with known error margins to morphometric data collected from a decedent. Recent research relating to the formulation of sex estimation standards has focussed on the assessment of bones other than the traditionally favoured pelvis and cranium, such as long bones of the appendicular skeleton. In particular, sex estimation standards based on morphometric data from metacarpals and phalanges have reported classification accuracy rates of 80% (and above) based on a narrow range of populations. The purpose of this study is to provide population-specific hand bone sex-estimation standards for a contemporary Western Australian population. The present study examines digital right hand radiographs of 300 adults of known age, equally represented by sex. A total of 40 measurements were taken in each hand (metacarpals and proximal phalanges); the measurements were then analysed using univariate statistics and cross-validated direct and stepwise discriminant function analysis. All hand bone measurements were significantly sexually dimorphic, with a tendency for the width measurements to express a higher degree of dimorphism than the length measurements. A maximum cross-validated classification accuracy of 91% was achieved with a sex bias of -6%. The standards presented here can be used in future forensic investigations that require sex estimation of hand bones in a Western Australian population.

Journal of Forensic Sciences, 2007

The dentition is widely recognized as the set of developmental markers that appear to show the le... more The dentition is widely recognized as the set of developmental markers that appear to show the least variability against chronological age; these markers are thus widely used in forensic anthropological investigations. As a possible alternative, we investigate here the potential of mandibular morphology as a developmental marker for estimating age at death in subadults. The sample analyzed comprises 79 known age and sex subadult individuals of South African Bantu and African American origin. Linear measurements of ramus height were obtained from the mathematical conversion of three-dimensional landmark data. A series of regression analyses were then performed to predict age by using the measurement of ramus height; results were cross-validated using a jackknife procedure. Our results show that ramus height can be used to predict age in the subadult skeleton with accuracy, closely approaching that of standards based on the dentition (standard error rates are between €1.1 years and €2.4 years).

Journal of Forensic and Legal Medicine, 2013

The aim of this study was to compare the accuracy of Demirjian&am... more The aim of this study was to compare the accuracy of Demirjian's four dental development methods for forensic age assessment in a South Australian population. The sample comprised orthopantomograms (OPGs) of 408 sub-adult individuals (211 male; 197 female) with an age range of 4.9-14.5 years. The OPGs were obtained from various dental schools and clinics in urban Adelaide. The following Demirjian methods were evaluated: the original 7-tooth technique; the revised 7-tooth system; the 4-tooth method; and the alternate 4-tooth approach. The left mandibular teeth in each OPG were assessed and rated according to the eight stages (A-H) defined and illustrated in Demirjian et al.(5) Differences between chronological and estimated ages were calculated for males and females separately; 95% confidence intervals of mean age differences were calculated and ANOVA used to assess the significance of mean differences. When comparing all four methods there were significant differences overall (and in individual age groups) between mean chronological and estimated age in both sexes. In addition, each method consistently overestimated chronological age. We also demonstrate that the accuracy of the dental age methods evaluated varies in different subsets of an Australian population, a finding that parallels previous research in other global populations. Based on our analyses we conclude that population-specific standards based on dental maturity curves, as opposed to estimated ages, would provide more accurate and statistically robust age estimations.

Journal of Forensic and Legal Medicine, 2013

The aim of the study is to develop accurate stature estimation models for a contemporary Western ... more The aim of the study is to develop accurate stature estimation models for a contemporary Western Australian population from measurements of the feet and footprints. The sample comprises 200 adults (90 males, 110 females). A stature measurement, three linear measurements from each foot and bilateral footprints were collected from each subject. Seven linear measurements were then extracted from each print. Prior to data collection, a precision test was conducted to determine the repeatability of measurement acquisition. The primary data were then analysed using a range of parametric statistical tests. Results show that all foot and footprint measurements were significantly (P < 0.01-0.001) correlated with stature and estimation models were formulated with a prediction accuracy of ± 4.673 cm to ± 6.926 cm. Left foot length was the most accurate single variable in the simple linear regressions (males: ± 5.065 cm; females: ± 4.777 cm). This study provides viable alternatives for estimating stature in a Western Australian population that are equivalent to established standards developed from foot bones.

International Journal of Legal Medicine, 2014

Requisite to routine casework involving unidentified skeletal remains is the formulation of an ac... more Requisite to routine casework involving unidentified skeletal remains is the formulation of an accurate biological profile, including sex estimation. Choice of method(s) is invariably related to preservation and by association, available bones. It is vital that the method applied affords statistical quantification of accuracy rates and predictive confidence so that evidentiary requirements for legal submission are satisfied. Achieving the latter necessitates the application of contemporary population-specific standards. This study examines skeletal pelvic dimorphism in contemporary Western Australian individuals to quantify the accuracy of using pelvic measurements to estimate sex and to formulate a series of morphometric standards. The sample comprises pelvic multi-slice computer tomography (MSCT) scans from 200 male and 200 female adults. Following 3D rendering, the 3D coordinates of 24 landmarks are acquired using OsiriX® (v.4.1.1) with 12 inter-landmark linear measurements and two angles acquired using MorphDb. Measurements are analysed using basic descriptive statistics and discriminant functions analyses employing jackknife validation of classification results. All except two linear measurements are dimorphic with sex differences explaining up to 65 % of sample variance. Transverse pelvic outlet and subpubic angle contribute most significantly to sex discrimination with accuracy rates between 100 % (complete pelvis-10 variables) and 81.2 % (ischial length). This study represents the initial forensic research into pelvic sexual dimorphism in a Western Australian population. Given these methods, we conclude that this highly dimorphic bone can be used to classify sex with a high degree of expected accuracy.

International Journal of Legal Medicine, 2012

A current limitation of forensic practice in Western Australia is a lack of contemporary populati... more A current limitation of forensic practice in Western Australia is a lack of contemporary population-specific standards for biological profiling; this directly relates to the unavailability of documented human skeletal collections. With rapidly advancing technology, however, it is now possible to acquire accurate skeletal measurements from 3D scans contained in medical databases. The purpose of the present study, therefore, is to explore the accuracy of using cranial form to predict sex in adult Australians. Both traditional and geometric morphometric methods are applied to data derived from 3D landmarks acquired in CT-reconstructed crania. The sample comprises multi-detector computed tomography scans of 200 adult individuals; following 3D volume rendering, 46 anatomical landmarks are acquired using OsiriX (version 3.9). Centroid size and shape (first 20 PCs of the Procrustes coordinates) and the inter-landmark (ILD) distances between all possible pairs of landmarks are then calculated. Sex classification effectiveness of the 3D multivariate descriptors of size and shape and selected ILD measurements are assessed and compared; robustness of findings is explored using resampling statistics. Cranial shape and size and the ILD measurements are sexually dimorphic and explain 3.2 to 54.3 % of sample variance; sex classification accuracy is 83.5-88.0 %. Sex estimation using 3D shape appears to have some advantages compared to approaches using size measurements. We have, however, identified a simple and biologically meaningful single non-traditional linear measurement (glabella-zygion) that classifies Western Australian individuals according to sex with a high degree of expected accuracy (87.5-88 %).

International Journal of Legal Medicine, 2013

The statistical quantification of error and uncertainty is inherently intertwined with ascertaini... more The statistical quantification of error and uncertainty is inherently intertwined with ascertaining the admissibility of forensic evidence in a court of law. In the forensic anthropological discipline, the robustness of any given standard should not only be evaluated according to its stated error but by the accuracy and precision of the raw data (measurements) from which they are derived. In the absence of Australian contemporary documented skeletal collections, medical scans (e.g. multislice computed tomography-MSCT) offer a source of contemporary population-specific data for the formulation of skeletal standards. As the acquisition of morphometric data from clinical MSCT scans is still relatively novel, the purpose of this study is to assess validity of the raw data that is being used to formulate Australian forensic standards. Six human crania were subjected to clinical MSCT at a slice thickness of 0.9 mm. Each cranium and its corresponding volume-rendered three-dimensional MSCT image were measured multiple times. Whether differences between MSCT and dry bone interlandmark measurements are negligible is statistically quantified; intra- and inter-observer measurement error is also assessed. We found that traditional bone measurements are more precise than their MSCT counterparts, although overall differences between the two data acquisition methods are negligible compared to sample variance. Cranial variation accounted on average for more than 20× the variance explained by MSCT vs. bone measurements. Similarly, although differences between operators were sometimes significant compared to intra-operator variance, they were negligible when compared to sample variance, which was on average 12× larger than that due to inter-operator differences.

HOMO - Journal of Comparative Human Biology, 2005

In order to compare linear dimensions made by traditional anthropometric techniques, and those ob... more In order to compare linear dimensions made by traditional anthropometric techniques, and those obtained from three-dimensional coordinates, samples of four indigenous southern African populations were analysed. Linear measurements were obtained using mathematically transformed, three-dimensional landmark data on 207 male crania of Cape Nguni, Natal Nguni, Sotho and Shangaan. Univariate comparisons for accuracy of the transformed linear data were made with those in a traditional linear study by de Villiers (The Skull of the South African Negro: A Biometrical and Morphological Study. Witwatersrand University Press, Johannesburg) on similar samples and equivalent landmarks. Comparisons were not made with her Penrose (Ann Eugenics 18 (1954) 337) analysis as an apparently anomalous 'shape'-'size' statistic was found. The univariate comparisons demonstrated that accurate linear measurements could be derived from three-dimensional data, showing that it is possible to simultaneously obtain data for three-dimensional geometric 'shape' and linear interlandmark analyses. Using Penrose and canonical variates analyses of the transformed three-dimensional interlandmark measurements, similar population distances were found for the four indigenous southern African populations. The inter-population distance relationships took the form of three separated pairs of distances, with the within-pair distances very similar in size. The cranial features of the four populations were found to be overall very similar morphometrically. However the populations were each shown by CVA to have population specific features, and using discriminant analyses 50% or more of the individual crania (with the exception of the Sotho) could be referred to their correct populations.

Forensic Science, Medicine, and Pathology, 2008

Methods for skeletal identification have a long history in physical and forensic anthropology. Re... more Methods for skeletal identification have a long history in physical and forensic anthropology. Recent literature demonstrates that new methods are constantly being developed, concurrent with refinements to those already commonly employed. The present study concerns the application of geometric morphometrics to assess the potential of mandibular morphology as a developmental marker for estimating age at death in subadult human skeletal remains. The sample comprises 79 known age and sex subadult individuals of South African Bantu and African American origin; 38 bilateral three-dimensional landmarks were designed and acquired using a portable digitizer. Linear regression was used to predict age using the multivariate descriptors of mandible size and shape based on configurations of three-dimensional landmarks. Our results show that the mandible can be used to predict age in the subadult skeleton with accuracy comparable to standards based on the dentition (standard error rates are between ±1.3 and ±3.0 years). These results closely parallel our previous study using the linear measurement of ramus height, but suggest that geometric morphometrics may be slightly more accurate when adolescents are included in the sample.

Forensic Science International, 2012

In Australia, particularly Western Australia, there is a relative paucity of contemporary populat... more In Australia, particularly Western Australia, there is a relative paucity of contemporary population-specific morphometric standards for the estimation of sex from unknown skeletal remains. This is largely a historical artefact from lacking, or poorly documented, repositories of human skeletons available for study. However, medical scans, e.g. MSCT (multislice spiral computed tomography) are an ingenious and practical alternative source for contemporary data. To that end, this study is a comprehensive analysis of sternal sexual dimorphism in a sample of modern Western Australian (WA) individuals with a main purpose to develop a series of statistically robust standards for the estimation of sex. The sample comprises thoracic MSCT scans, with a mean of 0.9 millimeter (mm) slice thickness, on 187 non-pathological sterna. Following 3D volume rendering, 10 anatomical landmarks were acquired using OsiriX(®) (version 3.9) and a total of 8 inter landmark linear measurements were calculated using Morph Db (an in-house developed database application). Measurements were analyzed using basic descriptive statistics and discriminant function analyses, with statistical analyses performed using SPSS 19.0. All measurements are sexually dimorphic and sex differences explain 9.8-47.4% of sample variance. The combined length of the manubrium and body, sternal body length, manubrium width, and corpus sterni width at first sternebra contribute significantly to sex discrimination and yield the smallest sex-biases. Cross-validated classification accuracies, i.e., univariate, stepwise and direct function, are 72.2-84.5%, with a sex bias of less than 5%. We conclude that the sternum is a reliable element for sex estimation among Western Australians.

Forensic Science International, 2013

An important component of forensic investigation is the identification of deceased (and increasin... more An important component of forensic investigation is the identification of deceased (and increasingly living) individuals, which is often the role of the forensic anthropologist. One of the most valuable steps towards identification is via a biological profile, developed through the application of population specific standards. In disaster victim identification scenarios, fleshed feet are often recovered in footwear; footprints are another potential source of trace evidence found at crime scenes. In medico-legal investigations, feet and footprints can be useful for extrapolating living height, it is thus expedient to determine whether sex can be estimated from the same anthropometric data. The aim of the present study is to develop accurate sex estimation standards for a contemporary Western Australian population from measurements of the feet and footprints. The sample comprises 200 adults (90 males, 110 females). Three bilateral linear measurements were taken from each foot and seven bilateral measurements were acquired from static footprints obtained using a Podograph. A precision test was first conducted to assess data accuracy and reliability. Measurement data are then analysed using a range of parametric statistical tests. Results show that males were significantly (P<0.001) larger than females for all foot and footprint measurements; cross-validated sex classification accuracies ranged from 71% to 91%. Although in many instances the sex bias was large (>±5%), this study provides viable alternatives for estimating sex in Western Australian individuals with accuracy equivalent to established standards developed from foot bones.

Forensic Science International, 2012

Forensic Science International, 2013

It is widely accepted that the most accurate statistical estimations of biological attributes in ... more It is widely accepted that the most accurate statistical estimations of biological attributes in the human skeleton (e.g., sex, age and stature) are produced using population-specific standards. As we previously demonstrated that the application of foreign standards to Western Australian individuals results in an unacceptably large sex bias (females frequently misclassified), the need for population-specific standards is duly required and greatly overdue. We report here on the first morphometric cranial sexing standards formulated specifically for application in, and based on the statistical analysis of, contemporary Western Australian individuals. The primary aim is to investigate the nature of cranial sexual dimorphism in this population and outline a series of statistically robust standards suitable for estimating sex in the complete bone and/or associated diagnostic fragments. The sample analysed comprised multi-detector computed tomography cranial scans of 400 individuals equally distributed by sex. Following 3D volume rendering, 31 landmarks were acquired using OsiriX, from which a total of 18 linear inter-landmark measurements were calculated. Measurements were analysed using basic descriptive statistics and discriminant function analyses employing jackknife validations of classification results. All measurements (except frontal breadth and orbital height - Bonferroni corrected) are sexually dimorphic with sex differences explaining 3.5-48.9% of sample variance. Bizygomatic breadth and maximum length of the cranium and the cranial base contribute most significantly to sex discrimination; the maximum classification accuracy was 90%, with a -2.1% sex-bias. We conclude that the cranium is both highly dimorphic and a reliable bone for estimating sex in Western Australian individuals.

Forensic Science International, 2012

As part of the formulation of a biological profile, the estimation of stature is an important ele... more As part of the formulation of a biological profile, the estimation of stature is an important element that provides useful data towards narrowing the pool of potentially matching identities. Recent literature has demonstrated that anthropometry of the hand has considerable promise for the accurate estimation of stature; although the technique has only been tested in a relatively limited range of populations. The aim of the present study, therefore, is to assess the reliability and accuracy of using anthropometric hand measurements for the estimation of stature in a contemporary Western Australian population; we also evaluate whether stature can be accurately estimated from the measurement of handprints. The study sample comprises 91 male and 110 female adult individuals. Following the measurement of stature, seven measurements are taken on each hand and its corresponding print. To establish the reliability of acquiring these measurements, a precision study was performed prior to primary data collection. Measurements data are analysed using basic univariate statistics and simple and multiple regression analyses. Our results show that the degree of measurement error and reliability are well within accepted standards. Stature prediction accuracy using hand and handprint measurements ranges from ±4.74 to 6.53cm, which is comparable to established skeletal standards for the hand. This study provides new forensic standards for the estimation of stature in a Western Australian population and also demonstrates that the measurement and analysis of handprints affords a novel source of profiling data that is statistically quantified.

Forensic Science International, 2014

In the present global socio-political scenario, an increasing demand exists for age estimation in... more In the present global socio-political scenario, an increasing demand exists for age estimation in living persons, such as refugees and asylum seekers, who seldom have any documentation for proof of identity. Age estimation in the living poses significant challenges because the methods need to be non-invasive, accurate and ethically viable. Methods based on the analysis of the pulp chamber are recommended for age estimation in living adults. There is, however, a paucity of studies of this nature and population specific standards in Western Australia. The aim of the present study is therefore, to test the reliability and applicability of the method developed by Kvaal et al. (1995) for the purpose of developing age estimation standards for an adult Western Australian population. A total of 279 digital orthopantomograms (143 female; and 136 male) of Australian individuals were analysed. A subset of the total sample (50) was removed as a cross-validation (holdout) sample. Following the method described in Kvaal et al. (1995), length and width measurements of the tooth and pulp chamber were acquired in maxillary central and lateral incisors; second premolars, mandibular lateral incisors; canines and first premolars. Those measurements were then used to calculate a series of ratios (length and width), which were subsequently used to formulate age estimation regression models. The most accurate model based on a single tooth was for the maxillary central incisor (SEE ±9.367 years), followed by the maxillary second premolar (SEE ±9.525 years). Regression models based on the measurement of multiple teeth improved age prediction accuracy (SEE ±7.963 years). The regression models presented here have expected accuracy rates comparable (if not higher than) to established skeletal morphoscopic methods. This method, therefore, offers a statistically quantified methodological approach for forensic age estimation in Western Australian adults.

Australian Journal of Forensic Sciences, 2019

The histological analysis of bone for forensic application requires thin sections to be prepared ... more The histological analysis of bone for forensic application requires thin sections to be prepared from extracted bone of suitable quality for visualization through conventional light microscopy and (if required) the measurement of microstruc-tural features, such as osteons. While a number of protocols for the preparation of thin sections exist, they are often time consuming and complex, or require expensive and non-portable equipment. A revised protocol is presented for obtaining high quality thin sections for light microscopy and histological analyses , tested in fresh, fixed, and dry archaeological cortical bone. It does not require extensive experience, or expensive materials or equipment, and can be further adapted for use with manual tools if necessary.

British Journal of Midwifery, 2015

ABSTRACT

Forensic Science International, 2015

Age estimation in the juvenile skeleton primarily relies on the assessment of the degree of denta... more Age estimation in the juvenile skeleton primarily relies on the assessment of the degree of dental and skeletal development relative to full maturity. The timing of the mineralization and eruption of the teeth is a sequential process that, compared to skeletal growth and development, is less affected by extrinsic influences such as nutrition and/or chronic illness. Accordingly, radiographic visualization and analysis of different tooth formation stages are the foundation for a number of widely applied age estimation standards. Presently, however, there is a relative paucity of contemporary dental age estimation standards for a Western Australian population. To that end, the aim of the present study is to develop statistically quantified radiographic age estimation standards for a Western Australian juvenile population. A total of 392 digital orthopantomograms (202 male and 190 female) of Western Australian individuals are analyzed. Following, Moorrees et al. (J. Dent. Res. 42 (1963a) 490-502; Am. J. Phys. Anthropol. 21 (1963) 205-213), dental development and root resorption was assessed. Alveolar eruption was analyzed following Bengston (Northwest Univ. Bull. 35 (1935) 3-9). Stages of dental development were used to formulate a series of age estimation polynomial regression models; prediction accuracy (±0.998 to 2.183 years) is further validated using a cross-validation (holdout) sample of 30 film orthopantomograms. A visual atlas of dental development and eruption was subsequently designed for the pooled sex sample. The standards presented here represent a non-invasive and statistically quantified approach for accurate dental age estimation in Western Australian juvenile individuals.

International journal of legal medicine, Jan 15, 2014

The clavicle is the first bone to ossify in the developing embryo and the last to complete epiphy... more The clavicle is the first bone to ossify in the developing embryo and the last to complete epiphyseal union. It is the latter sustained period of growth that has attracted the interest of skeletal biologists and forensic practitioners alike, who collectively recognize the important opportunity this bone affords to estimate skeletal age across the prenatal to early adult lifespan. Current research is largely directed towards evaluating the applicability of assessing fusion in the medial epiphysis, specifically for determining age of majority in the living. This study aims to contribute further insights, and inform medicolegal practice, by evaluating the Schmeling five-stage system for the assessment of clavicular development in a Western Australian population. We retrospectively evaluated high-resolution multiple detector computed tomography (MDCT) scans of 388 individuals (210 male; 178 female) between 10 and 35 years of age. Scans are viewed in axial and multiplanar reconstructed (...

Forensic Science International, 2014

The forensic anthropologist is responsible for contributing to the identification of an unknown b... more The forensic anthropologist is responsible for contributing to the identification of an unknown by constructing a biological profile from their skeletal remains. Towards achieving this goal, anthropologists can apply population and temporally specific standards with known error margins to morphometric data collected from a decedent. Recent research relating to the formulation of sex estimation standards has focussed on the assessment of bones other than the traditionally favoured pelvis and cranium, such as long bones of the appendicular skeleton. In particular, sex estimation standards based on morphometric data from metacarpals and phalanges have reported classification accuracy rates of 80% (and above) based on a narrow range of populations. The purpose of this study is to provide population-specific hand bone sex-estimation standards for a contemporary Western Australian population. The present study examines digital right hand radiographs of 300 adults of known age, equally represented by sex. A total of 40 measurements were taken in each hand (metacarpals and proximal phalanges); the measurements were then analysed using univariate statistics and cross-validated direct and stepwise discriminant function analysis. All hand bone measurements were significantly sexually dimorphic, with a tendency for the width measurements to express a higher degree of dimorphism than the length measurements. A maximum cross-validated classification accuracy of 91% was achieved with a sex bias of -6%. The standards presented here can be used in future forensic investigations that require sex estimation of hand bones in a Western Australian population.

Journal of Forensic Sciences, 2007

The dentition is widely recognized as the set of developmental markers that appear to show the le... more The dentition is widely recognized as the set of developmental markers that appear to show the least variability against chronological age; these markers are thus widely used in forensic anthropological investigations. As a possible alternative, we investigate here the potential of mandibular morphology as a developmental marker for estimating age at death in subadults. The sample analyzed comprises 79 known age and sex subadult individuals of South African Bantu and African American origin. Linear measurements of ramus height were obtained from the mathematical conversion of three-dimensional landmark data. A series of regression analyses were then performed to predict age by using the measurement of ramus height; results were cross-validated using a jackknife procedure. Our results show that ramus height can be used to predict age in the subadult skeleton with accuracy, closely approaching that of standards based on the dentition (standard error rates are between €1.1 years and €2.4 years).

Journal of Forensic and Legal Medicine, 2013

The aim of this study was to compare the accuracy of Demirjian&am... more The aim of this study was to compare the accuracy of Demirjian's four dental development methods for forensic age assessment in a South Australian population. The sample comprised orthopantomograms (OPGs) of 408 sub-adult individuals (211 male; 197 female) with an age range of 4.9-14.5 years. The OPGs were obtained from various dental schools and clinics in urban Adelaide. The following Demirjian methods were evaluated: the original 7-tooth technique; the revised 7-tooth system; the 4-tooth method; and the alternate 4-tooth approach. The left mandibular teeth in each OPG were assessed and rated according to the eight stages (A-H) defined and illustrated in Demirjian et al.(5) Differences between chronological and estimated ages were calculated for males and females separately; 95% confidence intervals of mean age differences were calculated and ANOVA used to assess the significance of mean differences. When comparing all four methods there were significant differences overall (and in individual age groups) between mean chronological and estimated age in both sexes. In addition, each method consistently overestimated chronological age. We also demonstrate that the accuracy of the dental age methods evaluated varies in different subsets of an Australian population, a finding that parallels previous research in other global populations. Based on our analyses we conclude that population-specific standards based on dental maturity curves, as opposed to estimated ages, would provide more accurate and statistically robust age estimations.

Journal of Forensic and Legal Medicine, 2013

The aim of the study is to develop accurate stature estimation models for a contemporary Western ... more The aim of the study is to develop accurate stature estimation models for a contemporary Western Australian population from measurements of the feet and footprints. The sample comprises 200 adults (90 males, 110 females). A stature measurement, three linear measurements from each foot and bilateral footprints were collected from each subject. Seven linear measurements were then extracted from each print. Prior to data collection, a precision test was conducted to determine the repeatability of measurement acquisition. The primary data were then analysed using a range of parametric statistical tests. Results show that all foot and footprint measurements were significantly (P < 0.01-0.001) correlated with stature and estimation models were formulated with a prediction accuracy of ± 4.673 cm to ± 6.926 cm. Left foot length was the most accurate single variable in the simple linear regressions (males: ± 5.065 cm; females: ± 4.777 cm). This study provides viable alternatives for estimating stature in a Western Australian population that are equivalent to established standards developed from foot bones.

International Journal of Legal Medicine, 2014

Requisite to routine casework involving unidentified skeletal remains is the formulation of an ac... more Requisite to routine casework involving unidentified skeletal remains is the formulation of an accurate biological profile, including sex estimation. Choice of method(s) is invariably related to preservation and by association, available bones. It is vital that the method applied affords statistical quantification of accuracy rates and predictive confidence so that evidentiary requirements for legal submission are satisfied. Achieving the latter necessitates the application of contemporary population-specific standards. This study examines skeletal pelvic dimorphism in contemporary Western Australian individuals to quantify the accuracy of using pelvic measurements to estimate sex and to formulate a series of morphometric standards. The sample comprises pelvic multi-slice computer tomography (MSCT) scans from 200 male and 200 female adults. Following 3D rendering, the 3D coordinates of 24 landmarks are acquired using OsiriX® (v.4.1.1) with 12 inter-landmark linear measurements and two angles acquired using MorphDb. Measurements are analysed using basic descriptive statistics and discriminant functions analyses employing jackknife validation of classification results. All except two linear measurements are dimorphic with sex differences explaining up to 65 % of sample variance. Transverse pelvic outlet and subpubic angle contribute most significantly to sex discrimination with accuracy rates between 100 % (complete pelvis-10 variables) and 81.2 % (ischial length). This study represents the initial forensic research into pelvic sexual dimorphism in a Western Australian population. Given these methods, we conclude that this highly dimorphic bone can be used to classify sex with a high degree of expected accuracy.

International Journal of Legal Medicine, 2012

A current limitation of forensic practice in Western Australia is a lack of contemporary populati... more A current limitation of forensic practice in Western Australia is a lack of contemporary population-specific standards for biological profiling; this directly relates to the unavailability of documented human skeletal collections. With rapidly advancing technology, however, it is now possible to acquire accurate skeletal measurements from 3D scans contained in medical databases. The purpose of the present study, therefore, is to explore the accuracy of using cranial form to predict sex in adult Australians. Both traditional and geometric morphometric methods are applied to data derived from 3D landmarks acquired in CT-reconstructed crania. The sample comprises multi-detector computed tomography scans of 200 adult individuals; following 3D volume rendering, 46 anatomical landmarks are acquired using OsiriX (version 3.9). Centroid size and shape (first 20 PCs of the Procrustes coordinates) and the inter-landmark (ILD) distances between all possible pairs of landmarks are then calculated. Sex classification effectiveness of the 3D multivariate descriptors of size and shape and selected ILD measurements are assessed and compared; robustness of findings is explored using resampling statistics. Cranial shape and size and the ILD measurements are sexually dimorphic and explain 3.2 to 54.3 % of sample variance; sex classification accuracy is 83.5-88.0 %. Sex estimation using 3D shape appears to have some advantages compared to approaches using size measurements. We have, however, identified a simple and biologically meaningful single non-traditional linear measurement (glabella-zygion) that classifies Western Australian individuals according to sex with a high degree of expected accuracy (87.5-88 %).

International Journal of Legal Medicine, 2013

The statistical quantification of error and uncertainty is inherently intertwined with ascertaini... more The statistical quantification of error and uncertainty is inherently intertwined with ascertaining the admissibility of forensic evidence in a court of law. In the forensic anthropological discipline, the robustness of any given standard should not only be evaluated according to its stated error but by the accuracy and precision of the raw data (measurements) from which they are derived. In the absence of Australian contemporary documented skeletal collections, medical scans (e.g. multislice computed tomography-MSCT) offer a source of contemporary population-specific data for the formulation of skeletal standards. As the acquisition of morphometric data from clinical MSCT scans is still relatively novel, the purpose of this study is to assess validity of the raw data that is being used to formulate Australian forensic standards. Six human crania were subjected to clinical MSCT at a slice thickness of 0.9 mm. Each cranium and its corresponding volume-rendered three-dimensional MSCT image were measured multiple times. Whether differences between MSCT and dry bone interlandmark measurements are negligible is statistically quantified; intra- and inter-observer measurement error is also assessed. We found that traditional bone measurements are more precise than their MSCT counterparts, although overall differences between the two data acquisition methods are negligible compared to sample variance. Cranial variation accounted on average for more than 20× the variance explained by MSCT vs. bone measurements. Similarly, although differences between operators were sometimes significant compared to intra-operator variance, they were negligible when compared to sample variance, which was on average 12× larger than that due to inter-operator differences.

HOMO - Journal of Comparative Human Biology, 2005

In order to compare linear dimensions made by traditional anthropometric techniques, and those ob... more In order to compare linear dimensions made by traditional anthropometric techniques, and those obtained from three-dimensional coordinates, samples of four indigenous southern African populations were analysed. Linear measurements were obtained using mathematically transformed, three-dimensional landmark data on 207 male crania of Cape Nguni, Natal Nguni, Sotho and Shangaan. Univariate comparisons for accuracy of the transformed linear data were made with those in a traditional linear study by de Villiers (The Skull of the South African Negro: A Biometrical and Morphological Study. Witwatersrand University Press, Johannesburg) on similar samples and equivalent landmarks. Comparisons were not made with her Penrose (Ann Eugenics 18 (1954) 337) analysis as an apparently anomalous 'shape'-'size' statistic was found. The univariate comparisons demonstrated that accurate linear measurements could be derived from three-dimensional data, showing that it is possible to simultaneously obtain data for three-dimensional geometric 'shape' and linear interlandmark analyses. Using Penrose and canonical variates analyses of the transformed three-dimensional interlandmark measurements, similar population distances were found for the four indigenous southern African populations. The inter-population distance relationships took the form of three separated pairs of distances, with the within-pair distances very similar in size. The cranial features of the four populations were found to be overall very similar morphometrically. However the populations were each shown by CVA to have population specific features, and using discriminant analyses 50% or more of the individual crania (with the exception of the Sotho) could be referred to their correct populations.

Forensic Science, Medicine, and Pathology, 2008

Methods for skeletal identification have a long history in physical and forensic anthropology. Re... more Methods for skeletal identification have a long history in physical and forensic anthropology. Recent literature demonstrates that new methods are constantly being developed, concurrent with refinements to those already commonly employed. The present study concerns the application of geometric morphometrics to assess the potential of mandibular morphology as a developmental marker for estimating age at death in subadult human skeletal remains. The sample comprises 79 known age and sex subadult individuals of South African Bantu and African American origin; 38 bilateral three-dimensional landmarks were designed and acquired using a portable digitizer. Linear regression was used to predict age using the multivariate descriptors of mandible size and shape based on configurations of three-dimensional landmarks. Our results show that the mandible can be used to predict age in the subadult skeleton with accuracy comparable to standards based on the dentition (standard error rates are between ±1.3 and ±3.0 years). These results closely parallel our previous study using the linear measurement of ramus height, but suggest that geometric morphometrics may be slightly more accurate when adolescents are included in the sample.

Forensic Science International, 2012

In Australia, particularly Western Australia, there is a relative paucity of contemporary populat... more In Australia, particularly Western Australia, there is a relative paucity of contemporary population-specific morphometric standards for the estimation of sex from unknown skeletal remains. This is largely a historical artefact from lacking, or poorly documented, repositories of human skeletons available for study. However, medical scans, e.g. MSCT (multislice spiral computed tomography) are an ingenious and practical alternative source for contemporary data. To that end, this study is a comprehensive analysis of sternal sexual dimorphism in a sample of modern Western Australian (WA) individuals with a main purpose to develop a series of statistically robust standards for the estimation of sex. The sample comprises thoracic MSCT scans, with a mean of 0.9 millimeter (mm) slice thickness, on 187 non-pathological sterna. Following 3D volume rendering, 10 anatomical landmarks were acquired using OsiriX(®) (version 3.9) and a total of 8 inter landmark linear measurements were calculated using Morph Db (an in-house developed database application). Measurements were analyzed using basic descriptive statistics and discriminant function analyses, with statistical analyses performed using SPSS 19.0. All measurements are sexually dimorphic and sex differences explain 9.8-47.4% of sample variance. The combined length of the manubrium and body, sternal body length, manubrium width, and corpus sterni width at first sternebra contribute significantly to sex discrimination and yield the smallest sex-biases. Cross-validated classification accuracies, i.e., univariate, stepwise and direct function, are 72.2-84.5%, with a sex bias of less than 5%. We conclude that the sternum is a reliable element for sex estimation among Western Australians.

Forensic Science International, 2013

An important component of forensic investigation is the identification of deceased (and increasin... more An important component of forensic investigation is the identification of deceased (and increasingly living) individuals, which is often the role of the forensic anthropologist. One of the most valuable steps towards identification is via a biological profile, developed through the application of population specific standards. In disaster victim identification scenarios, fleshed feet are often recovered in footwear; footprints are another potential source of trace evidence found at crime scenes. In medico-legal investigations, feet and footprints can be useful for extrapolating living height, it is thus expedient to determine whether sex can be estimated from the same anthropometric data. The aim of the present study is to develop accurate sex estimation standards for a contemporary Western Australian population from measurements of the feet and footprints. The sample comprises 200 adults (90 males, 110 females). Three bilateral linear measurements were taken from each foot and seven bilateral measurements were acquired from static footprints obtained using a Podograph. A precision test was first conducted to assess data accuracy and reliability. Measurement data are then analysed using a range of parametric statistical tests. Results show that males were significantly (P<0.001) larger than females for all foot and footprint measurements; cross-validated sex classification accuracies ranged from 71% to 91%. Although in many instances the sex bias was large (>±5%), this study provides viable alternatives for estimating sex in Western Australian individuals with accuracy equivalent to established standards developed from foot bones.

Forensic Science International, 2012

Forensic Science International, 2013

It is widely accepted that the most accurate statistical estimations of biological attributes in ... more It is widely accepted that the most accurate statistical estimations of biological attributes in the human skeleton (e.g., sex, age and stature) are produced using population-specific standards. As we previously demonstrated that the application of foreign standards to Western Australian individuals results in an unacceptably large sex bias (females frequently misclassified), the need for population-specific standards is duly required and greatly overdue. We report here on the first morphometric cranial sexing standards formulated specifically for application in, and based on the statistical analysis of, contemporary Western Australian individuals. The primary aim is to investigate the nature of cranial sexual dimorphism in this population and outline a series of statistically robust standards suitable for estimating sex in the complete bone and/or associated diagnostic fragments. The sample analysed comprised multi-detector computed tomography cranial scans of 400 individuals equally distributed by sex. Following 3D volume rendering, 31 landmarks were acquired using OsiriX, from which a total of 18 linear inter-landmark measurements were calculated. Measurements were analysed using basic descriptive statistics and discriminant function analyses employing jackknife validations of classification results. All measurements (except frontal breadth and orbital height - Bonferroni corrected) are sexually dimorphic with sex differences explaining 3.5-48.9% of sample variance. Bizygomatic breadth and maximum length of the cranium and the cranial base contribute most significantly to sex discrimination; the maximum classification accuracy was 90%, with a -2.1% sex-bias. We conclude that the cranium is both highly dimorphic and a reliable bone for estimating sex in Western Australian individuals.

Forensic Science International, 2012

As part of the formulation of a biological profile, the estimation of stature is an important ele... more As part of the formulation of a biological profile, the estimation of stature is an important element that provides useful data towards narrowing the pool of potentially matching identities. Recent literature has demonstrated that anthropometry of the hand has considerable promise for the accurate estimation of stature; although the technique has only been tested in a relatively limited range of populations. The aim of the present study, therefore, is to assess the reliability and accuracy of using anthropometric hand measurements for the estimation of stature in a contemporary Western Australian population; we also evaluate whether stature can be accurately estimated from the measurement of handprints. The study sample comprises 91 male and 110 female adult individuals. Following the measurement of stature, seven measurements are taken on each hand and its corresponding print. To establish the reliability of acquiring these measurements, a precision study was performed prior to primary data collection. Measurements data are analysed using basic univariate statistics and simple and multiple regression analyses. Our results show that the degree of measurement error and reliability are well within accepted standards. Stature prediction accuracy using hand and handprint measurements ranges from ±4.74 to 6.53cm, which is comparable to established skeletal standards for the hand. This study provides new forensic standards for the estimation of stature in a Western Australian population and also demonstrates that the measurement and analysis of handprints affords a novel source of profiling data that is statistically quantified.

Forensic Science International, 2014

In the present global socio-political scenario, an increasing demand exists for age estimation in... more In the present global socio-political scenario, an increasing demand exists for age estimation in living persons, such as refugees and asylum seekers, who seldom have any documentation for proof of identity. Age estimation in the living poses significant challenges because the methods need to be non-invasive, accurate and ethically viable. Methods based on the analysis of the pulp chamber are recommended for age estimation in living adults. There is, however, a paucity of studies of this nature and population specific standards in Western Australia. The aim of the present study is therefore, to test the reliability and applicability of the method developed by Kvaal et al. (1995) for the purpose of developing age estimation standards for an adult Western Australian population. A total of 279 digital orthopantomograms (143 female; and 136 male) of Australian individuals were analysed. A subset of the total sample (50) was removed as a cross-validation (holdout) sample. Following the method described in Kvaal et al. (1995), length and width measurements of the tooth and pulp chamber were acquired in maxillary central and lateral incisors; second premolars, mandibular lateral incisors; canines and first premolars. Those measurements were then used to calculate a series of ratios (length and width), which were subsequently used to formulate age estimation regression models. The most accurate model based on a single tooth was for the maxillary central incisor (SEE ±9.367 years), followed by the maxillary second premolar (SEE ±9.525 years). Regression models based on the measurement of multiple teeth improved age prediction accuracy (SEE ±7.963 years). The regression models presented here have expected accuracy rates comparable (if not higher than) to established skeletal morphoscopic methods. This method, therefore, offers a statistically quantified methodological approach for forensic age estimation in Western Australian adults.

The histological analysis of bone for forensic application requires thin sections to be prepared ... more The histological analysis of bone for forensic application requires thin sections to be prepared from extracted bone of suitable quality for visualisation through conventional light microscopy and (if required) the measurement of microstructural features, such as osteons. There are a number of protocols available for the preparation of cortical bone thin sections; however they usually involve multiple complicated steps, in addition to requiring specific (and often expensive) equipment or a dedicated histopathology laboratory. The preparation of a sample for histological analysis may involve any or all of the following steps: fixation; dehydration; impregnation (typically under vacuum); embedding; cutting; grinding/polishing; and mounting for microscopy. As a result histological preparation can be particularly time consuming dependent on the number of steps in the protocol, and the fixation, drying and embedding resin curing time. Expensive and/or non-portable equipment and extensive preparation times make most protocols unsuitable for application in a field laboratory, while the cost of most histopathology equipment such as microtomes and resin impregnation and embedding systems can be prohibitive.

In this presentation we describe a revised protocol for obtaining high quality thin sections for light microscopy and histological analyses in fresh or fixed cortical bone. The method has been simplified and does not require extensive experience, expensive materials or equipment. The proposed protocol was tested first on a sample of fresh kangaroo bone and formalin fixed canine bone, before being applied to formalin fixed human bone and dry archaeological human bone specimens. The described method reduces the number of steps involved in preparation of thin sections from fresh or fixed cortical bone. It can be used for more fragile dry or archaeological material with additional preparation. The method does not require expensive histology equipment or a dedicated histopathology laboratory and can thus be adapted for use in a field laboratory setting.