Sex estimation from measurements of the calcaneus: Applications for personal identification in Thailand

Age Estimation Using Machine Learning Algorithms with Parameters Obtained from X-ray Images of the Calcaneus

BACKGROUND

Determination of bone age is a critical issue for forensics, surgery, and basic sciences.

AIM

This study aims to estimate age with high accuracy and precision using Machine Learning (ML) algorithms with parameters obtained from calcaneus x-ray images of healthy individuals.

METHOD

The study was carried out by retrospectively examining the foot X-ray images of 341 people aged 18-65 years. Maximum width of the calcaneus (MW), body width (BW), maximum length (MAXL), minimum length (MINL), facies articularis cuboidea height (FACH), maximum height (MAXH), and tuber calcanei width (TKW) parameters were measured from the images. The measurements were then grouped as 20-45 years of age, 46-64 years of age, 65 and older, and age estimation was made by using these at the input of ML models.

RESULTS

As a result of the ML input of the measurements obtained, a 0.85 Accuracy (Acc) rate was obtained with the Extra Tree Classifier algorithm. The accuracy rate of other algorithms was found to vary between 0.78 and 0.82. The contribution of parameters to the overall result was evaluated by using the shapley additive explanations (SHAP) analyzer of Random Forest algorithm and the MAXH parameter was found to have the highest contribution in age estimation.

CONCLUSIONS

As a result of our study, calcaneus bone was found to have high accuracy and precision in age estimations.

Diagnostic accuracy of paranasal sinus measurements on multislice computed tomography for sex estimation: A systematic review, meta-analysis, and meta-regression

This systematic review aimed to answer the question, "Are paranasal measurements obtained with multislice computed tomography able to accurately estimate sex?" This PROSPERO-registered systematic review included six databases and gray literature. Meta-analysis of linear and volumetric data was performed using a random-effects model, mean differences (MDs), and inverse variance. The QUADAS-2 tool-related risk of bias (RoB) and certainty evidence (GRADE approach) were assessed. A total of 1651 articles were initially selected from the main electronic databases for title and abstract screening. After removing duplicates and studies that did not meet the inclusion criteria, 18 studies were eligible for the meta-analysis. The screened studies included 2507 computed tomography of non-pathologic paranasal sinuses of adults aged between 18 and 40 years. Frontal sinus (FS) width (-4.89 mm; p < 0.00001) and maxillary sinus (MS) height (-3.73 mm; p < 0.00001) showed the greatest MD between females and males. Regarding volume, the MD was significant (p < 0.00001) in both paranasal sinuses (-3.01 and -1.04 cm³ , respectively). The best sensitivity (ability to identify males) and specificity (ability to identify females) were found for the anteroposterior (72.3%) and intermaxillary (69%) MS distances, respectively. In general, all studies exhibited low RoB and applicability concerns. The certainty of the evidence was categorized as very low to moderate. Both paranasal sinuses were shown to be dimorphic structures, which could be valuable tools for forensic identification using the FS width and MS anteroposterior distance measurements. However, heterogeneity among studies must be considered.

Gender determination in adults using calcaneal diameters from lateral foot X-ray images in the Iranian population

Background: Using morphologic features of the bones is the basis of gender determination in anthropology and forensic medicine. In this study, we evaluated the calcaneus diameters for gender determination in the Iranian population.

Methods: This cross-sectional study was conducted on Iranians referring to Hazrat-e Rasool Hospital’s radiology ward for plain lateral X-ray of the foot. Lateral foot X-rays from 100 men and 100 women were gathered and evaluated for calcaneal indexes. These patients aged between 18 and 80 years old who did not suffer major trauma to the calcaneus bone were recruited. Using a picture archiving and communication system (PACS), four variables were calculated for each X-ray graph: Maximum anterior-posterior length of the calcaneus (MAXL), Maximum height of the bone (MAXH), Height of the cuboid facet (CFH) and Height the calcaneal body (BH). Cut off points for each index were calculated using the area under curve (AUC) in ROC curves.

Results: Lateral foot X-rays from 100 men and 100 women were gathered and evaluated for calcaneal indexes. The means of the four indexes were compared between the sexes which showed all four means are significantly different p value <0.001. AUC for MAXL in differentiating the genders was 0.824, which showed 86.8 as the cut off with a sensitivity of 80% and specificity of 69.0%. Cut off point for MAXH was set at 59.8 with sensitivity and specificity of 78.0% and 60.0%, respectively. For BH, 49.5 was set as the cut off point with a sensitivity of 79.0% and specificity of 64.0%. The best cut off point for CFH was 27.8 with 76.0% sensitivity and 63.0% specificity.

Conclusion: It can be concluded that the calcaneal diameters are reliable criteria for sex determination. Although the cutoff points are different between various races and populations, it is evident that these diameters can be used for sex determination in general.

The importance of human osteological collections: Our past, present, and future

The thesis of this brief exposition is the absolute and immediate necessity of preserving existing osteological collections. Once lost, they can never be replaced. They are priceless, historically and culturally. Each collection is unique, in content and in scientific value. No one collection is complete, or replicates any other. These collections are separated by space and by time, by geography and by epoch. They preserve our past, as well as our understanding of human variation. They help us to better understand the human condition and contribute to the advancement of many disciplines including: anthropology, medicine, surgery, anatomy, history, and, undeniably, forensic anthropology. In spite of their uniqueness, all osteological collections face similar challenges: cultural norms and sensitivities, funding, space limitations, and competing priorities. This article provides a succinct overview of several private and public collections around the world, the challenges of preservation, and the benefits of their salvation. The skeletal collections described here are but a sample of what is, and of what may be lost. Anything more would require a book. Anything less would be an irreplaceable and tragic loss.

Morphological analysis of Gissane's angle utilising a statistical shape model of the calcaneus

INTRODUCTION

Gissane's crucial angle (GA) facilitates to diagnose calcaneal fractures, and serves as an indicator of the quality of anatomical reduction after fixation. The study aimed to utilise statistical shape models (SSM) for analysing the complex 3D surface anatomy of the calcaneus represented by the simplified GA measurement on lateral radiographs.

MATERIALS AND METHODS

SSMs were generated from CT scans of paired adult calcanei from 10 Japanese and 31 Thai specimens. GA measurements in 3D and 2D were obtained for the lateral, central and medial anatomy of the posterior facet and sinus tarsi. The correlation between calcaneal length and GA was analysed. Regression and principal component (PC) analyses were conducted for analysing morphological variability in calcaneal shape relating to GA. The bilateral symmetry of the obtained measurements was analysed.

RESULTS

The mean GA (lateral) for the Japanese specimens was 105.1° ± 7.5 and 105.4° ± 8.5 for the Thai. The projected 2D angles of the central and medial measurements were larger (P < 0.00) than the 3D values. The medial projected 2D angles were larger (P ≤ 0.02) compared to the lateral. Despite the bilateral symmetry of GA and calcaneal length, their correlation displayed clear signs of asymmetry, which was confirmed by regression and PC analyses.

CONCLUSIONS

Japanese and Thai specimens revealed lower GAs (both range and mean) compared to reported reference values of other ethnicities. As a reduced GA is generally indicative of a calcaneal fracture, our results are important to surgeons for their diagnostic assessment of Japanese and Thai patients. The results indicate that the GA measurement on a plain radiograph is a simplified representation of the lateral-to-central 3D calcaneal anatomy but significantly underestimates the angle measurement on the medial aspects of the respective surface areas.

Evaluation of computed tomography images of calcaneus for estimation of sex

Estimation of sex from bone remnants after medicolegal issues or mass disasters constitute a challenge. Our objective was to investigate if morphometric measurements performed on computed tomography (CT) images of the calcaneus can be useful for sex estimation. The measurements were performed on CT images of calcaneus bones of 489 patients (203 women, 286 men). The parameters under investigation were maximum length (MAXL), load arm length (LAL), minimum breadth (MINB), body height (BH), maximum height (MAXH), dorsal articular facet length (DAFL), dorsal articular facet breadth (DAFB), and cuboidal facet height (CFH). All parameters were remarkably increased in men compared to women (p < 0.001, for all). The highest performances for sex estimation were displayed by DAFL (92.8%) and BH (92.6%). The concomitant use of variables MAXL, BH, CFH, and DAFL revealed accuracy as high as 96% for gender discrimination. We suggest that morphometric measurements performed on CT images of the calcaneus can provide useful data for the estimation of sex.

Accuracies of discriminant function equations for sex estimation using long bones of upper extremities

One of the scopes of practice of forensic anthropologists is the estimation of sex from skeletal remains. As a result, population-specific discriminant function equations have been developed from measurements of various bones of the human skeletons. Steyn, Patriquin (Forensic Sci Int 191 (1-3):113, 2009) noted that the lack of skeletal collections and data from most parts of the world has made this process impractical. Previous attempts to develop global discriminant function equations from measurements of the pelvis showed that population-specific equations are not necessary as equations derived from other populations yielded high sex estimation scores when applied to a different population. However, information on the suitability and applicability of generalised equations in sex estimation using long bones is still scarce. It is, therefore, the aim of this study to assess the accuracies of population-specific discriminant function equations derived from measurements of long bones of the upper limb of South African population groups. Data analysed in the current study were obtained from Mokoena, Billings, Bidmos, Mazengenya (Forensic Sci Int 278:404, 2017) and Mokoena, Billings, Gibbon, Bidmos, Mazengenya (Science & Justice 6(59):660-666, 2019) in which a total sample of 988 bones (humeri, radii, and ulnae) of South Africans of African descent (SAAD), South Africans of European descent (SAED) and Mixed Ancestry South Africans (MASA) were measured. Stepwise and direct discriminant function analyses were performed on the pooled data. Each function was used to estimate the sex of cases in each population group separately and average accuracies calculated. Thereafter, population-specific discriminant function equations were formulated for each population group and then applied to other population groups. The average accuracies of functions for pooled data ranged between 80.7 and 86.5%. The cross-validation average accuracies remained unchanged for most functions, confirming the validity of derived functions. A drop in average accuracies (0.8-5.3%) was observed when the functions were tested on a sample of SAAD while increased average accuracy was observed for the SAED and MASA (0.5-6.9%). When population-specific functions for a particular population group were applied to other groups, a wide range of a drop in average accuracies was observed (1.3 to 22.4%). This thereby confirms that population-specific equations should not be applied to other population groups. However, discriminant function equations from the pooled data of South Africans are accurate in the estimation of sex and efforts should be made towards the development and validation of such equations from as many bones of the human skeleton.

Anthropometry of the human calcaneus and orientation of the articular facet for the cuboid bone as a basis for anatomically correct positioning of osteosynthetic screws in fracture treatment

PURPOSE

Fractures of the calcaneus are reported most commonly in the tarsal region. Their incidence is highest among active people in productive age. As such, optimal treatment can have vast implications for patients. The study aimed to compare calcaneal proportions of the Czech population in the last centuries to present day, for a precise choice and positioning of the osteosynthetic material, and its safe implantation in the anterior part of the calcaneus. Furthermore, we describe the frequency of the calcaneocuboid joint involvement in calcaneal fractures.

METHODS

We obtained 69 macerated (dry) human calcanei from anatomical collections along with multiplanar reconstructions obtained from 43 serial CT scans from patients with injuries other than calcaneal fractures. Specimens were measured using a modified set of Bidmos et al. criteria (2006). Two groups (CT scans of macerated specimens and patients' CT scans) were statistically evaluated and compared with the help of an experienced statistician. Furthermore, scans of 80 surgically treated patients were retrospectively assessed for calcaneocuboid joint involvement.

RESULTS

The median tilt of the calcaneocuboid joint in the transverse plane was 67° in the anatomical specimens and 72° in the multiplanar reconstructed CT scans taken from patients with intact tarsal regions. These results suggest that the length of screws should be ideally in the range between 21.3 and 25mm. In 47.3% of the patients presenting with a fractured calcaneus, the calcaneocuboid joint was involved. There was a statistically significant difference in most of the variables observed between the two groups.

CONCLUSION

As the calcaneocuboid joint involvement appears to be present in up to 50% of cases, adequate care should be taken. To maximize the biomechanical properties of the construct and to minimize the risks, our findings suggest the screws should be at an inner tilt of 68-74° from the lateral calcaneal wall and be of 23.5-26.2mm length. However, due to differences between the two groups and the small sample size, further investigation is needed.

Sex estimation from upper limb bones in a Thai population

Sex estimation from skeletal remains is an important practice for forensic human identification. The aims of this study were to assess sexual dimorphism and to develop discriminant function equations for sex estimation using 12 measurements of upper limb bones (humerus, ulna, and radius) in a Thai population. The sample consisted of 228 Thai skeletons (114 males and 114 females) from the Forensic Osteology Research Center, Chiang Mai University, Chiang Mai, Thailand. All skeletal length variables were measured according to the Standards for Data Collection from Human Skeletal Remains. The values of measurements were used to develop the sex estimation equations using univariate and multivariate discriminant function analyses. The results of sexual dimorphism showed that upper limb bone lengths of males were statistically significantly longer than those of females in all dimensions (P<0.05). For univariate discriminant function analysis, the results showed that the epicondylar breadth of the humerus, the physiological length of the ulna, and the antero-posterior diameter at the midshaft of the radius were the best indicators for sex estimation in the humerus, ulna, and radius, respectively. Moreover, the multivariate discriminant function equation using all variables of the ulna and radius was the best indicator for sex estimation. In conclusion, the discriminant function equations derived from upper limb bone measurements provided highly accurate sex estimation in Thai samples. Therefore, these equations using humerus, radius, and ulna measurements can be applied for sex estimation with good accuracy in Thais.

Estimating sex from the seven cervical vertebrae: An analysis of two European skeletal populations

Methods for estimating sex from a variety of skeletal elements is vital in forensic anthropology as many of the traditionally studied bones are often fragmented upon recovery. The current study examined the seven cervical vertebrae to establish an accurate sex estimation method for Europeans. Discriminant functions were developed from the seven cervical vertebrae using the maximum body height (CHT), vertebral foramen anterior-posterior diameter (CAP), and vertebral foramen transverse diameter (CTR). To date, no study has used these variables to estimate sex from human remains. Two hundred and ninety-five adult individuals (157 males, 138 females) from the University of Athens and the Luis Lopes skeletal collections were studied. No population differences were exhibited between the contemporary Greek and historic Portuguese skeletons, indicating that discriminant functions for sex estimation from the cervical vertebrae may not be population- or temporally-specific. The results of this study indicate that only CHT and CTR exhibited statistically significant sexual dimorphism. Seven multivariate discriminant functions were developed with accuracy rates between 80.3% and 84.5%. Cross-validation studies showed that five of the seven functions exhibited strong statistical algorithms. This study will assist with estimating the sex of unknown Europeans from the cervical vertebrae especially in cases where more accurate predictors of sex, such as the skull or the pelvis, are unavailable.

Three-Dimensional Morphological Variations of the Human Calcaneus Investigated Using Geometric Morphometrics

The shape of the calcaneus determines the mechanical interaction of the foot with the ground during the heel-strike in human walking. Detailed knowledge of the pattern of sexual dimorphism of the human calcaneus could help to clarify the pathogenetic mechanism of foot and knee disorders, which are more prevalent in females. Therefore, the aim of this study was to characterize and visualize the three-dimensional shape variations of the calcaneus in relation to sex and age using geometric morphometrics. Computed tomography images of 56 feet without subtalar injuries or disorders were used in this study. Thirty-seven anatomical landmarks were identified on the bone model of the calcaneus to calculate principal components (PCs) of shape variations among specimens. The PC scores were compared between males and females, and their correlations with age were also analyzed. The female calcaneus was longer in length and shorter in height than that of males. The medial process of the calcaneal tuberosity in females was more inferiorly projected and the tuberosity was shifted more laterally. Also, the calcaneus was wider and the sustentaculum tali thickened with aging. Female structural features of the calcaneus alter the kinematics of the foot during walking and could be a structural factor in foot and knee disorders. This study contributes to a comprehensive understanding of shape variations in the human calcaneus. Clin. Anat., 33:751-758, 2020. © 2019 Wiley Periodicals, Inc.

Distal Humerus Morphological Variation and Sex Estimation in Modern Thai Individuals

Due to differential preservation, it is necessary to develop sex estimation methods on varied anatomical regions, including the distal humerus. Sexually dimorphic differences of the medial epicondyle angle, olecranon fossa shape, trochlear extension, and trochlear constriction have been documented in several non-Asian groups. This study examines distal humerus morphological variation in 616 modern Thai individuals (f = 198; m = 418) 18-96 years old and tests the methods on a hold-out sample of 152 individuals (f = 91; m = 61). The results indicate that population-specific binary probit regression performs the best (74.1-100%), followed by composite scoring (77.0-90.1%), binary logistic regression (63.3-92.2%), and univariate sectioning points (37.7-90.1%). Age minimally effects the expression of the medial epicondyle angle in males, and trait scoring is susceptible to high intra- and interobserver error. While demonstrating relatively high sex biases, distal humerus morphology can be used to estimate the sex of Thai individuals when more sexually dimorphic regions are absent.

Reliability of palatal rugoscopy for sexual dimorphism in forensic dentistry: A systematic literature review and meta-analysis

OBJECTIVE

This study aimed to assess the validity of palatal rugoscopy for sexual dimorphism in the casework routine of forensic dentistry.

DESIGN

A systematic literature reviews was established following the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) and Cochrane guidelines. Six electronic databases were searched as the primary source of information. "Grey literature" was included to avoid selection and publication bias. As a secondary source of information, the reference lists of the eligible studies were also consulted to increase the search spectrum. Methodological quality and risk of bias were assessed with Joanna Briggs Institute Critical Appraisal Tools for Systematic Reviews. Statistic tests, namely the meta-analysis of diagnostic accuracy, Cochran Q test, and I2 test, were performed to verify the heterogeneity between the eligible studies.

RESULTS

The systematic search resulted in 263 studies, out of each 8 fulfilled the inclusion criteria. An additional eligible article was included after the search in reference lists. From the 9 studies that underwent qualitative data extraction, six were selected for quantitative analysis. The meta-analysis of grouped sex estimates showed sensitivity and specificity rates of 89% and 83%, respectively. The Area Under the Curve reached 0.93. High heterogeneity and important methodological limitations were detected among the studies.

CONCLUSION

Palatal rugoscopy seems to have discriminant power for sexual dimorphism. However, the limitations found specifically in each study and the strong heterogeneity across studies suggest that palatal rugoscopy lacks evidence-based confirmation for reliable application as a sole tool for sexual dimorphism in practice.