Precision and intersite correlation of bone densitometry at the radius, tibia and femur with peripheral quantitative CT

Objective. To compare the in situ precision of peripheral quantitative CT (pQCT) at the radius, tibia and femur, and to analyze the intersite correlation, in order to determine whether measurements at the lower extremity reproduce results at the radius or are of additional informative value. Design and material. pQCT measurements were performed in 86 elderly cadavers (mean age 80.5 years) at trabecular and cortical locations in the radius, tibia and femur, determining densitometric (bone mineral content and density) as well as geometric parameters (cross-sectional area, cortical thickness, polar moment of inertia and others). In 14 cadavers, repeated measurements were obtained at all sites on four different days. Results and conclusions. At cortical sites, the precision for the densitometric and geometric variables ranged from 0.4% to 4.3%, and was similar for the radius, tibia and femur. At trabecular locations, the reproducibility of the density measurements ranged from 1.8% to 2.5% at the radius, and from 3.2% to 5.9% at the femur and tibia. The intersite correlation of the total bone mineral content ranged from 0.87 and 0.97 at cortical sites, and from 0.63 to 0.85 at trabecular locations. The trabecular density showed a higher similarity between the tibia and femur (r=0.68–0.78) than between the radius and the lower extremity (r=0.41–0.45). The results demonstrate a substantial heterogeneity of trabecular bone in elderly individuals and advocate measurements directly at the site of clinical or scientific interest. Received: 5 July 1999 Revision requested: 12 August 1999 Revision received: 31 August 1999 Accepted: 13 September 1999     

Cranium asymmetry in a modern Greek population sample of known age and sex

The aim of this paper is to evaluate and quantify cranium asymmetry, sexual differences in the set of individual asymmetry scores, and the relationship between fluctuating asymmetry and age, in a modern Greek population sample. In addition, we test for the developmental origins of health and disease hypothesis by assessing the correlation between fluctuating asymmetry and cause of death. The study sample consisted of 173 crania of known sex and adult age (92 males, 81 females) belonging to individuals who lived in Greece during the twentieth century. The three-dimensional coordinates of 77 ectocranial landmarks were digitized using a Microscribe 3DX contact digitizer and landmark configurations were analyzed using the generalized least-squares Procrustes method. Regarding directional asymmetry, the results show that the human skull has a tendency for a left-side excess for the Greek population. No significant directional asymmetry differences between the sexes are found. The highest levels of fluctuating asymmetry for both sexes are located on the skull base. The levels of fluctuating asymmetry in all cranial regions appear higher for males than females. Nevertheless, these differences do not present any statistical significance between sexes. Additionally, there is no relationship between fluctuating asymmetry scores and age for both males and females. Finally, the results of this study could not confirm that early development has a significant impact on adult health outcomes.

     

Age-related changes in the craniofacial region in a modern Greek population sample of known age and sex

The aim of this paper is to investigate ageing changes in craniofacial region in both sexes and evaluate whether these shape changes are substantial to achieve age discrimination of samples used in anthropological analyses. The study sample consisted of 157 crania of known sex and age (81 males and 76 females) belonging to individuals who lived in Greece during the twentieth century. The sample was divided in three age groups: young adults (YA, 18–39 years old), middle adults (MA, 40–59 years old) and old adults (OA, >60 years old). The three-dimensional coordinates of 31 ecto-cranial landmarks were digitized using a Microscribe 3DX contact digitizer, and landmark configurations were analyzed using the generalized least-squares Procrustes method. The results indicate that both males and females show significant difference among the age groups; however, shape differences can not be used for age group discrimination due to a large range on the accuracy of age group classification. The morphometric changes related to age were different between sexes.

     

Preliminary study on sexual dimorphism of metric traits of cranium and mandible in a modern Italian skeletal population and review of population literature

This study aims to assess the sexual dimorphism of skull in a modern skeletal collection through a direct anthropometric methodology by using a logistic regression analysis as statistical approach in order to provide specific regression formulae for the Italian population.Thirtyfour measurements (24 from cranium, 10 from mandible; 33 linear distances, one angle) were taken on 80 individuals (40 males, 40 females). A stepwise discriminant function analysis selected the combination of variables which best discriminated between sexes, and a cross-validation assessed the accuracy rate of the original sample.Most distances resulted longer in males than in females, but differences were statistically significant only for 12 and 6 out of respectively 24 cranium and 10 mandibular distances. Five combined cranium features returned a prediction accuracy of 88.6% (y = −81.01 + 0.14* Maximum cranial length + 0.16* Basion-bregma height −0.05* Cranial base length +0.20* Bizygomatic breadth +0.31* Nasal height; adjusted R² = 47.0%). Nine mandibular features were required to reach 74.7% accuracy (y = −93.08 + 0.19* Bigonial width +0.14* Bicondylar breadth +0.11* Mandibular length +0.18* Height of the mandibular body at mental foramen +0.21* Chin height −0.09* Mandibular angle −0.06* Minimum ramus breadth −0.05* Maximum ramus height −0.01* Maximum ramus breadth; adjusted R² = 23.92%).Current results and existing literature suggested that only few cranial measurements can be used for diagnosis of sex: the same variables showed similar accuracy in different ethnic contexts. In conclusion, some aspects of sexual dimorphism of skull seem to be independent from ancestry.     

Sex estimation of the tibia in modern Turkish: A computed tomography study

The utilization of computed tomography is beneficial for the analysis of skeletal remains and it has important advantages for anthropometric studies. The present study investigated morphometry of left tibia using CT images of a contemporary Turkish population. Seven parameters were measured on 203 individuals (124 males and 79 females) within the 19–92-years age group. The first objective of this study was to provide population-specific sex estimation equations for the contemporary Turkish population based on CT images. A second objective was to test the sex estimation formulae on Southern Europeans by Kranioti and Apostol (2015). Univariate discriminant functions resulted in classification accuracy that ranged from 66 to 86%. The best single variable was found to be upper epiphyseal breadth (86%) followed by lower epiphyseal breadth (85%). Multivariate discriminant functions resulted in classification accuracy for cross-validated data ranged from 79 to 86%. Applying the multivariate sex estimation formulae on Southern Europeans (SE) by Kranioti and Apostol in our sample resulted in very high classification accuracy ranging from 81 to 88%. In addition, 35.5–47% of the total Turkish sample is correctly classified with over 95% posterior probability, which is actually higher than the one reported for the original sample (25–43%). We conclude that the tibia is a very useful bone for sex estimation in the contemporary Turkish population. Moreover, our test results support the hypothesis that the SE formulae are sufficient for the contemporary Turkish population and they can be used safely for criminal investigations when posterior probabilities are over 95%.     

Reconstruction of femur length from its proximal fragments in a Bulgarian modern population

Estimation of stature from bones has anthropological and forensic importance. It is well known that the intact femur has the highest correlation with stature. However, the intact femur is not always recovered in forensic cases. The current study introduces a method of estimating the length of femur from partial proximal elements specific to the Bulgarian population. One-hundred and forty adult femora belonging to known age and sex were studied. The method is based on several landmarks and distance between them, such as vertical head diameter, transverse diameter of the head, maximum head diameter, head circumference, sagittal subtrochanteric diameter, transverse subtrochanteric diameter and supero-inferior neck diameter. Simple and multiple linear regressions were obtained to define these estimates. For males, regression formula, which included head circumference measurement, provided the best fit of the data, resulting in the highest correlation and lowest standard error of estimate compared with all other variables. For females, the vertical diameter of the head showed the best correlation with maximum length. A combination of all variables into a single equation only improved the standard error of the estimate. The regression formula suggested that the proximal end is the best estimator of femur length. The derived formulae are population and sex specific.     

A preliminary investigation of cranial sexual dimorphism in a Northern Territory population

ABSTRACT

In the discipline of forensic anthropology, the concept of population specificity ensures that the most accurate methodologies are applied to a given set of skeletal remains. It has been shown that the use of sex estimation standards derived using a population that is temporally and/or geographically removed from the population of the decedent results in misclassification and an unacceptably large sex bias. The current study explores the latter by applying two established cranial sex estimation standards, Giles and Elliot (1963) and Franklin (2013), to a previously untested population from the Northern Territory, Australia. The results demonstrate a reduction in classification accuracy when applying both standards, with an increase in the sex bias for all discriminant functions tested. These results indicate that utilizing foreign standards to estimate sex within the Northern Territory will likely result in misclassification, thus indicating the need for more accurate standards that reflect the sexual dimorphism in the contemporary Northern Territory population.     

Estimation of stature using fragmentary femur and tibia lengths in a Thai population

Stature estimation is one of the most important parameters for human identification. The current study aimed to investigate the relationship between stature and femur and tibia measurements other than length in modern Thai skeletons, and to derive regression equations that can be used for living stature estimation when complete bones are unavailable. The sample consisted of 159 males and 96 females. We used two analytical methods, i.e. direct 1-step and indirect 2-step. Results showed that the upper breadth of the femur from males and the maximum anteroposterior diameter of the lateral condyle from females were the best estimators of stature. Maximum proximal breadth of the tibia showed the lowest standard error values in males and females. The derived equations were tested on a holdout sample in which the distal breadth of the tibia exhibited the lowest mean absolute error in both males and females, while in the femur measurements, the maximum anteroposterior diameter of the lateral condyle produced the lowest mean absolute error in males, and an absolute mean value from vertical head diameter in females. The present study suggests that measurements taken from damaged bones can be used for stature estimation.     

Morphometric evaluation of the foramen magnum for sex determination: A study from Saudi Arabia

The present study provides a database of various morphometric dimensions of the foramen magnum region in the Saudi population. The objective of this study was to evaluate various measurements of the foramen magnum region for sex determination in the Saudi population by using computed tomography (CT) images. The various radiological measurements of the foramen magnum region were measured in a total of 200 adult subjects of Saudi origin including 100 males and 100 females. Sexual dimorphism was observed in five parameters related to the foramen magnum, namely length of the right occipital condyle (LROC), length of the left occipital condyle (LLOC), width of the foramen magnum (WFM), area of the foramen magnum (AFM) and length of the foramen magnum (LFM). The accuracy to discriminate sex ranged from 65.5% to 62.5% when LROC, LLOC, WFM, AFM, and LFM were considered as individual parameters. When multiple parameters were combined to discriminate sex, the highest accuracy of 71% was achieved.     

Human bony labyrinth as a sex indicator in subadults

Due to the durability and good preservation of the petrous bone in archaeological and forensic contexts, the value of the inner ear as a sex indicator has been evaluated in various studies. Previous findings suggest that the morphology of the bony labyrinth is not stable in the postnatal period. In this study, we aim to assess the sexual dimorphism of the bony labyrinth via analysis of computed tomography (CT) data obtained from 170 subadults (birth to 20 y.o.) and test whether the postnatal changes of the bony labyrinth affect the level of dimorphism in the inner ear. A set of 10 linear measurements of 3D labyrinth models as well as 10 size and shape indices were analyzed. Sexually dimorphic variables were used to produce sex estimation formulae with discriminant function analysis. The produced formulae allowed for the correct classification of up to 75.3 % of individuals aged from birth to 15 years old. Sexual dimorphism was not significant for individuals between 16 and 20 years of age. This study suggests that the morphology of the subadult bony labyrinth exhibits significant sexual dimorphism in individuals under 16 years of age, which can aid the forensic identification process. Although postnatal growth of the temporal bone seems to affect the level of sexual dimorphism present in the inner ear, the formulae created in this study could be used as an additional tool for sex estimation of subadult (<16 y.o.) remains.     

Estimation of stature and sex from scapular measurements by three-dimensional volume-rendering technique using in Chinese

In order to develop population – specific discriminant function equations and stature prediction equations for predicting sex and stature from measurements of the scapula in a contemporary Chinese, 414 individual 3D CT images were collected from participants undergoing routine examination. Sex differences for the variables were tested by Student’s t-test. Fisher’s method has been followed for discriminant analysis. Regression analysis was applied to match the six linear parameters against stature. The stepwise analysis of all measurements yielded a sex classification accuracy rate of 86.7% and a sex bias of 3.1%. All the classification accuracy rates of the univariate discriminant function analyses are of more than 80%. For stature estimation, the accuracy of stature prediction ranged from 5.252 to 7.210 cm for male, from 4.630 to 6.484 cm for female, respectively. This paper provides indications that the scapula is an important bone for sex diagnosis and it could be effectively used as alternatives in forensic cases. Furthermore, the equations presented for stature estimation in this study should be used as alternatives in forensic cases when long bones were unavailable for stature estimation.     

A web application for sex and stature estimation from radiographic proximal femur for a Thai population

In both forensic and archaeological domains, the discovery of incomplete human remains is a frequent occurrence. Nevertheless, the estimation of biological profiles from such remains presents a challenge due to the absence of crucial skeletal elements, such as the skull and pelvis. This study aimed to assess the utility of the proximal femur in the forensic identification process by creating a web application for osteometric analysis of the proximal femur. The aim was to determine the sex and stature of an individual from radiographs of the left anteroposterior femur. To accomplish this, an automated method was developed for acquiring linear measurements from radiographic images of the proximal femur using Python tools. The application of Hough techniques and Canny edge detection was utilized to generate linear femoral dimensions from radiographs. A total of 354 left femora were radiographed and measured by the algorithm. The sex classification model employed in this study was the Naïve Bayes algorithm (accuracy = 91.2 %). Results indicated that Gaussian process regression (GPR) was the most effective method for estimating stature (mean error = 4.68 cm, SD = 3.93 cm). The proposed web application holds the potential to serve as a valuable asset in the realm of forensic investigations in Thailand, particularly in the estimation of biological profiles from fragmentary skeletal remains.     

Population specificity in the estimation of skeletal age and sex: case studies using a Western Australian population

ABSTRACT

The expertise of the forensic anthropologist is grounded in the study of skeletal morphology relative to normal state; the latter is variously defined according to the complex interrelationship between biological function, genetics and intra-specific variation (amongst others). In relation to sex estimation, there are multiple dimorphic attributes in the adult skeleton that facilitate accurate sex estimations. It is, however, well established that there are population specific influences in not only skeletal growth, but also the expression and magnitude of sexual dimorphism (notwithstanding relative consistency in ‘universally dimorphic traits’ that relate to biological functioning – e.g., pelvic shape in relation to female functional requirements for childbirth).

The recognition of the need for statistical quantification of forensic assessment is mandated by judicial requirement. Application of reference standards ‘foreign’ to that of the local jurisdiction, however, introduces an unknown variation and by association possible misclassifications. The present paper aims to empirically demonstrate the effect of the latter in a Western Australian population using multivariate classification statistics. We report here the analysis of a sample comprising three-dimensionally reconstructed cranial (n = 400) and pelvic (n = 400) multi-detector computed tomography (MDCT) thin-slice scans. In the morphometric analysis of cranial dimorphism, we demonstrate an unacceptably large sex bias; foreign standards thus frequently misclassify females.     

Development and validation of a new formula for sex estimation based on multislice computed tomographic measurements of maxillary and frontal sinuses among Brazilian adults

Objectives:To evaluate the accuracy of the measurements of the maxillary sinus (MS) and frontal sinus (FS) in sex estimation among Brazilian adults using multislice computed tomography (MCT) and to develop and cross-validate a new formula for sex estimation.Methods:The present cross-sectional research was conducted in two phases: (1) development of a formula on the basis of the measurements of both the sinuses (50 males and 50 females); and (2) validation study (20 males and 20 females). The linear measurements (height, width and diameter) were assessed using the RadiAnt DICOM software. A new formula for sex estimation was developed (multivariate statistical approach) and validated. Receiver operating characteristic curves, area under the curve, sensitivity, specificity, positive and negative predictive values, accuracy and likelihood ratio were estimated.Results:Males displayed higher mean values (width, height and diameter) of the FS and MS (p < 0.05). The MS was a better predictor in sex estimation (males vs females), compared to the FS (accuracy between 61–74% and 58–69%, respectively). The distance between the right and left MS displayed the highest accuracy (74%). The sensitivity, specificity and accuracy of the new formula were 80%, 95.5% and 87.5%, respectively. 63.1% reduction was observed in the number of predictive values for sex estimation (individuals older than 30 years).Conclusions:The present MCT measurements showed a higher accuracy in the estimation of sex in males. The highest accuracy was associated with the distance between the right and left MS. The new formula displayed high precision for sex estimation.     

Estimation of stature and sex from calcaneal measurements in Chinese

The calcaneus is a compact bone that is able to withstand high tensile forces and keep intact. Measurements of the calcaneus have been shown to be sexually dimorphic and used for stature estimation in different populations. In the present study, eight measurements for every calcaneal were taken from X-ray film of 293 Chinese, including five linear and three angular measurements. Discriminant function score equations were generated for use in sex determination, and five linear parameters were measured and matched against stature. The average accuracy of sex classification was 89.1% for the stepwise method, 78.2 to 82.3% for the direct method with linear measurements, and 52.6 to 58.7% for the direct method with angular measurements. However, the range of the standard errors of estimate is high in comparison with that obtained for stature estimation based on intact long bones and previous studies with the calcaneus in other populations. This paper provides indications that the calcaneus is an important bone for sex diagnosis and it could be effectively used as alternatives in forensic cases. However, the equations presented for stature estimation in this study should be used with caution in forensic cases when only the calcaneus is available for stature estimation.     

Estimation of the femur length from its proximal measurements in Anatolian Caucasians by artificial neural networks

Femora are a well preserved section of the skeleton after death. Therefore, they are commonly used in the field of forensic sciences, physical anthropology and anatomy. In addition, femur morphometry is helpful in finding sex or side (left or right) differences. The femur also shows characteristics of certain populations. Femur length is important for calculation of individual stature. In this study, the artificial neural network method was used to estimate femur length. In total, 230 femora exemplar were used. The three input parameters of the method were the distance between trochanter major top point and trochanter minor bottom point, the diameter of caput femoris and the diameter of collum femoris. By using these parameters, the artificial neural network estimation on femur length was performed. The results show that the method is capable of performing this estimation. In addition, sex discrimination was performed and achieved with 82% accuracy. As well as the identification of sex or side differences, morphometry of the proximal femur is necessary and important for surgical procedures.     

Determination of sex from the femur in Anatolian Caucasians: a digital radiological study

Determination of the sex is one of the most important steps when evaluating decomposed bodies or skeletal remnants. However, relevant data exhibit significant ethnic and temporal variation. This study provides information on in vivo femoral dimensions of Anatolian Caucasians. 50 males and 54 females with ages between 18 and 68 years were investigated with computed tomography. For males, mean maximum length (ML) was 448.2mm, mean vertical head diameter (VHD) was 48.8mm, mean midshaft transverse diameter (MTD) was 26.5mm, and mean anterior bowing (AB) was 759.3mm. For females, these were 419.0mm, 43.4mm, 25.6mm, and 779.5mm, respectively. Femoral dimensions of Anatolian Caucasians were not entirely similar to a single racial group that was already reported. There was a significant difference between males and females regarding ML and VHD (p<0.0001 for both). MTD and AB did not exhibit sexual dysmorphism. Discriminant analysis for sex type produced 83.3% accuracy when ML was used, and 76.9% accuracy when VHD was used (p<0.0001). Combined use of both parameters increased overall accuracy to 84.6% (p<0.0001). For VHD, cut-off value of 44.9mm produced 94% sensitivity and 83% specificity. For ML, cut-off value of 428.6 produced 80% sensitivity and 67% specificity.     

The subpubic angle in sex determination: Anthropometric measurements and analyses on Anatolian Caucasians using multidetector computed tomography datasets

Introduction and aimThe investigation of new anatomical criteria and revalidation of existing ones in sex determination for different populations are among main research foci of forensic anthropometry. In that context, the pelvis is the most extensively studied bone. A number of qualitative classifications, dimensional measurements and indices have been proposed for investigative anthropometry and forensic studies. Independent use of these parameters generally provided an accuracy rate of 70–75%. In this study, the accuracy rate of the subpubic angle in sex determination was investigated in living Anatolian Caucasians.Material and methodThe subpubic angle was identified and measured on three-dimensional computed tomographic images of pelves. Data were obtained using 64-detector computed tomography (MDCT) with an isotrophic resolution of 500 μm. The sample included 66 males (41.6 ± 14.9 years of age) and 43 females (41.1 ± 14.2 years of age). Measurements were taken on a dedicated three-dimensional image analysis workstation. The subpubic angle was electronically measured. The technique and methodology was validated on a standard skeletal model. Intraobserver agreement was analyzed with intraclass correlation coefficient, and intraobserver variability was evaluated with technical error of measurement (inter- and intra-observer TEM), relative technical error of measurement (rTEM) and coefficient of reliability (R) measures. The subpubic angle for the study group and for both sexes was reported as minimum–maximum (mean ± SD). Independent-Samples T Test for equality of means was used to determine the difference between the two sexes regarding the subpubic angle. The correlation between the subpubic angle and the age of subjects were using Pearson Correlation Coefficients in males and in females. Logistic regression model was used to classify subjects according to their sex. Receiver operating characteristic curve analysis was performed to determine a cut-off value for further studies and to test the performance of the binary classification test.ResultsIntraclass correlation for the subpubic angle (0.990), TEM (1082), rTEM (1.492), and R (0.990) represented almost complete reliability and accuracy of the measurement method. The subpubic angle was between 48° and 81° (65.9° ± 7.2°) in males and was between 64° and 100° (82.6° ± 7.7°) in females. Statistically significant difference was found between males and females regarding the subpubic angle (p < 0.0001). The subpubic angle was not significantly correlated with age in males (p = 0.953), or in females (r = 0.975). The accuracy of the subpubic angle in sex determination was 90.8%. With a cut-off value of 74°, sensitivity of subpubic angle to detect female phenotype was 88% and its specificity was 95%.ConclusionThe subpubic angle is an accurate parameter in sex determination with high sensitivity and specificity.     

Determination of sex from the patella in a contemporary Spanish population

The skull and pelvis have been used for the determination of sex for unknown human remains. However, in forensic cases where skeletal remains often exhibit postmortem damage and taphonomic changes the patella may be used for the determination of sex as it is a preservationally favoured bone. The goal of the present research was to derive discriminant function equations from the patella for estimation of sex from a contemporary Spanish population. Six parameters were measured on 106 individuals (55 males and 51 females), ranging in age from 22 to 85 years old, from the Granada Osteological Collection. The statistical analyses showed that all variables were sexually dimorphic. Discriminant function score equations were generated for use in sex determination. The overall accuracy of sex classification ranged from 75.2% to 84.8% for the direct method and 75.5%–83.8% for the stepwise method. When the South African White discriminant functions were applied to the Spanish sample they showed high accuracy rates for sexing female patellae (90%–95.9%) and low accuracy rates for sexing male patellae (52.7%–58.2%). When the South African Black discriminant functions were applied to the Spanish sample they showed high accuracy rates for sexing male patellae (90.9%) and low accuracy rates for sexing female patellae (70%–75.5%). The patella was shown to be useful for sex determination in the contemporary Spanish population.