Estimation of sex from the upper limb measurements of Sudanese adults

Sex estimation is the first biological attribute needed for personal identification from mutilated and amputated limbs or body parts in medical-legal autopsies. Populations have different sizes and proportions that affect the anthropometric assessment of sex. Relatively few published works assess the accuracy of sex estimation from soft tissue measurements of upper limb parts, except for the hand and its components, but these studies involve a limited range of global populations. The current study aimed to assess the degree of sexual dimorphism in upper limb measurements and the accuracy of using these measurements for sex estimation in a contemporary adult Sudanese population. The upper arm length, ulnar length, wrist breadth, hand length, and hand breadth of 240 right-handed Sudanese subjects (120 males and 120 females) aged between 25 and 30 years were measured by international anthropometric standards. Demarking points, sexual dimorphism indices and discriminant functions were developed from 200 subjects (100 males and 100 females) who composed the study group. All variables were sexually dimorphic. The ulnar length, wrist breadth and hand breadth significantly contributed to sex estimation. Forearm dimensions showed a higher accuracy for sex estimation than hand dimensions. Cross-validated sex classification accuracy ranged between 78.5% and 89.5%. The reliability of these standards was assessed in a test sample of 20 males and 20 females, and the results showed accuracy between 77.5% and 90%. This study provides new forensic standards for sex estimation from upper limb measurements of Sudanese adults.     

Sex estimation using foramen magnum measurements,discriminant analyses and artificial neural networks on an eastern Turkish population sample

BackgroundAlthough many studies have been conducted using the foramen magnum for sex estimation, recent findings have indicated that the discriminant and regression models obtained from the foramen magnum may not be reliable. Artificial Neural Networks, was used as a classification technique in sex estimation studies on some other bones, did not used in sex estimation studies on the foramen magnum until now. The aim of this study was sex estimation on an Eastern Turkish population sample using foramen magnum measurements, discriminant analyses and Artificial Neural Networks.MethodologyThe study was performed on the CT images of a total of 720 cases, comprising 360 males and 360 females. For sex estimation, discriminant analysis and Artificial Neural Networks were used.ResultsThe accuracy rate was 86.7% with discriminant analysis and when sex estimation accuracy was determined according to cases with posterior probabilities above 95%, the accuracy ranged from 0% to 33.3%. With the use of the discriminant formulas of 2 other studies, obtained from different Turkish samples, sex could be determined at a rate of 84.6%. Some formulas were found to be unsuccessful in sex estimation. Sex estimation accuracy of 88.2% was achieved with Artificial Neural Networks.ConclusionIn this study, it was found that sex could be determined to some extent with discriminant formulas from other samples from the same population, although some formulas were unsuccessful. With the use of image processing techniques and machine learning algorithms, better results can be obtained in sex estimation.     

Sex determination from the sternal end of the rib by osteometric analysis

BACKGROUND: The aim of this study was to establish a sample group of Turkish population to determine sex from the sternal end of the ribs. Sex determination from the human skeleton bones is a simple and specific method. MATERIALS AND METHODS: The specimens consisted of right fourth (4th) ribs of 78 females and 173 males of known age, sex and race during 1994-1997 in Izmir, Turkey. A discriminant function analysis showed that the most helpful parameter in the young group was superior-inferior height (SIH), and both SIH and anterior-posterior breadth (APB) in the older group. Modified discriminant score formulae for both young and old groups to determine sex for Turkish population was calculated. RESULTS: The results indicated that the accuracy of sex determination was 88.6% in the young group (phase 1-4, age 15-32), 86.5% in the older group (phase 5-8, age 33-89). CONCLUSIONS: This study indicates that sexual dimorphism can be assessable by using a single rib, right fourth rib in a Turkish population from ages 13 to 89. SIH of the rib is the most reliable parameter; APB follows it.     

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.     

Sex estimation from foramen magnum parameters in adult Turkish population: A computed tomography study

Identification of skeletal relics is crucial for medicolegal purposes. Sex estimation is one of the critical parts providing the identification of skeletal relics. In forensic practice, sex estimation requires multidisciplinary studies of such as forensic medicine, anatomy, dentistry and radiology. Recently, radiological studies on this subject have been increasing with the developing technology. The objective of this study is to examine the usage of radiological dimensions of foramen magnum for sex estimation in human skulls by developing discriminant functions in Turkish population. We analyzed 600 (300 males and 300 females) Computerized Tomography (CT) images of Turkish individuals aged between 21 and 50. Four measurements were obtained from CT images. All measurements in males were significantly greater than in females, and they provided the higher sex classification accuracy. The area of the foramen magnum calculated by Radinsky's formula was the best measurement for sex estimation with a 75% accuracy rate. In conclusion, the CT images of foramen magnum show sexual dimorphism in our population. To use population specific data would be the most appropriate approach for sex estimation.     

Estimation of sex based on patella measurements in a contemporary Chinese population using multidetector computed tomography: An automatic measurement method

Sex estimation is an important part of creating a biological profile, and ultimately assisting in creating a presumptive identification of unidentified skeletal remains. However, manual methods of anthropometric are time-consuming and prone to observer variability. The present study is an attempt to estimation of sex from automatic measurement of patella by multidetector computed tomography (MDCT) in a contemporary Chinese population. Four measurements for every patella, including maximum height (MAXH), maximum breadth (MAXB), maximum thickness (MAXT) and patellar volume (PV), were automatically provided by the software from CT image of 300 Chinese. The sample is composed of 156 males and 144 females with an average age of 41.44 and 45.68 years, respectively. The statistical analyses showed that all variables were sexually dimorphic. Receiver operating characteristic (ROC) analysis was performed to estimate sex from patella. The univariate analysis of each patellar parameter yielded a sex classification accuracy rate of 73.1% to 85.7%. The classification accuracy rates of sex estimation using the combination of the patellar parameters are 81.9% to 91.6%. This paper provides indications that the patella is important bone for sex estimation and it may be used as an alternative in forensic cases when the skull and pelvis are unavailable.     

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.     

Sex estimation from knee breadth dimensions in a Finnish population

Sex estimation is an important part of osteological analysis of skeletons and forensic identification process. Traditionally cranial and pelvic traits are utilized for accurate sex estimation. However, post-cranial measurements have also been proven to accurately estimate sex especially from robust bones such as the femur. In this study, we investigated the potential of knee breadth dimensions in sex estimation in a Finnish population. To conduct this study we utilized a study sample (n = 1654) belonging to the Northern Finland Birth Cohort 1966. All individuals were 46 years of age at the time of the examination. Three knee breadth dimensions were measured from subjects' knee posteroanterior radiographs: femoral biepicondylar breadth (FBEB), mediolateral breadth of the femoral condyles (FCML), and mediolateral breadth of the tibial plateau (TPML). Sex estimation was performed using logistic regression. The study clearly demonstrated that all three measurements were different between males and females. Sectioning points for individual knee breadth measurements were 82.9 mm for FBEB, 76.6 mm for FCML and 75.4 mm for TPML. The classification rates ranged from 90.9% to 93.6%. The less commonly used measurements of FCML and TPML showed higher accuracy than FBEB in sex estimation. Our study confirmed that knee breadths can be successfully utilized to improve sex estimation in cases where the skeleton is only partially preserved and other major components of sex estimation are absent. We can also provide new standards for sex estimation from the knee joint in a Finnish population.     

Determination of sex on the basis of hyoid bone measurements in a Japanese population using multidetector computed tomography

Sex determination for unidentified human remains is important because the determined sex is usually used as a foundation for the estimation of other biological profiles. This study investigated the sexual dimorphism of the adult hyoid bone and developed discriminant equations to accurately estimate sex in a contemporary Japanese population using measurements on two-dimensional computed tomography (CT) images. The study sample comprised 280 cadavers (140 males, 140 females) of known age and sex that underwent postmortem CT and subsequent forensic autopsy. In accordance with previous studies, seven measurements were performed using two-dimensional CT reconstructed images. Most measurements of males were significantly greater than those of females. The perpendicular length from the most anterior edge of the hyoid body to the line that connects the most distal points of the greater horns of the hyoid and the linear distance between the most lateral edges of the hyoid body most significantly contributed to sex determination. This study demonstrated that discriminant functions on the basis of three measurements provided higher rates of accurate sex classification (93.3–94.6%) than univariate functions. Therefore, the hyoid bone is highly sexually dimorphic in the contemporary Japanese population and may be useful in forensic contexts for sex determination with a high level of accuracy.

     

Tailored logistic regression models for sex estimation of unknown individuals using the published population data of the humeral epiphyses

This paper introduces a far-flung approach to formulate population independent models based on the humeral epiphyses as a supplementary tool for biological sex estimation of unknown partial remains. Resources for this study include the published summary statistics of 7 modern populations inhabited the continents of Africa, Asia, Europe, and South America. The regenerated humeral metric data (n = 1490) via truncation approach were modeled using logistic regression. Three fitted models were evaluated for applicability across populations on an independent test sample (n = 430). The experiment was assessed graphically and quantitatively using histogram of posterior probabilities and the classification table. The predictive power of the models was evaluated at the conventional (0.5) and high (0.95) posterior probability thresholds. It was found that the vertical humeral head model is insufficient for sex estimation especially in the European females due to different levels of interpopulation size variability. Interestingly, the distal biepicondylar breadth model showed overall better performance achieving the highest total and sex specific accuracies. Findings indicated that together, the epiphyseal measurements are capable of discriminating sex with overall accuracy of 90.2% which is raised up to 98.8% with 95% confidence of accurate estimates in more than 50% of the test sample. While evidences have been presented pointing to the biological and statistical meaningfulness of the humeral epiphyses model, the analysis allowed pinpointing the utility of the distal biepicondylar breadth model in sex diagnosis in transpopulation application settings. Additionally, few variables are needed to reach satisfactory sex prediction in a diverse sample.     

Sex estimation using diagonal diameter measurements of molar teeth in African American populations

Teeth are often recovered in forensic cases due to their postmortem longevity. The goal of the present research was to investigate the degree of sexual dimorphism in the permanent molars of African Americans using crown and cervical diagonal diameters. Discriminant functions developed from a modern Greek population were tested for accuracy of sex estimation in an African American population. One hundred and three (53 males and 50 females) individuals ranging in age from 16 years to 66 years old were used from the Robert J. Terry Anatomical Skeletal Collection. Four diagonal diameter measurements were taken for each of the left mandibular and maxillary molars: mesiobuccal-distolingual crown diameter, mesiolingual-distobuccal crown diameter, mesiobuccal-distolingual cervical diameter, and mesiolingual-distobuccal cervical diameter. The overall percentage of accuracy of the modern Greek discriminant functions when applied to the African American sample was between 53.8% and 63.6%. Males were more accurately classified (93.6%–100%) than females (0%–18.2%). The African American population specific direct discriminant functions showed accuracy rates from 72.6% to 100% for the original data and 40%–72.3% for the cross-validated data. The African American stepwise discriminant functions showed accuracy rates from 63.9% to 77.6% for the original and cross-validated data. Comparisons to other populations were made. The results suggest that, in teeth, there is variation in the degree of sexual dimorphism between populations and discriminant functions for sex estimation in dentition are population specific.     

Determination of sex from the hyoid bone in a contemporary White population

Six discriminant functions, developed from an historic White population, were tested on a contemporary White population for determination of sex from the hyoid. One hundred and thirty four fused and unfused hyoids from a contemporary White population were used. Individuals ranged between 20 and 49 years old. Six historic White discriminant functions were applied to the fused and unfused hyoids of the pooled contemporary White population, i.e. all males and females and all age ranges combined. The overall accuracy rates were between 72.1% and 92.3%. Correct sex determination for contemporary White males ranged between 88.2% and 96.3%, while correct sex determination for contemporary White females ranged between 31.3% and 92.0%. Discriminant functions were created for the contemporary White population with overall mean accuracy rates between 67.0% and 93.0%. The multivariate discriminant function overall accuracy rates were between 89.0% and 93.0% and the univariate discriminant function overall accuracy rates were between 67.0% and 86.8%. The contemporary White population data were compared to other populations and showed significant differences between many of the variables measured. This study illustrated the need for population-specific and temporally-specific discriminant functions for determination of sex from the hyoid bone.     

Age and sex estimation by metric measurements and fusion of hyoid bone in a Turkish population

The hyoid bone is of great importance in forensic medicine practice and it has been studied for various forensic purposes; however, there have been few studies dealing with age and sex estimation using the hyoid bone. Using discriminant function analysis this study attempts to determine the utility of metric measurements and non-metric variations of the hyoid bone in terms of estimation of sex and age in a Turkish population and to find out differences with other populations by comparison of obtained results with the literature. For this purpose, the hyoid bones of 85 cadavers of known sex and age were extracted and 33 measurements were made with a computer program following photography with a camera. In addition to these measurements, the degree of fusion of the greater cornua to the hyoid corpus was examined. Out of 33 measurements, 18 showed significant sex-related differences.There was a sharp rise in hyoid bone fusion in both males and females after the age of 60 years. However, no marked sex-related differences were observed regarding fusion. The unstandardised canonical discriminant function was estimated based on three variables, and the correct classification ratio was 77.4% for males and 81.3% for females. The obtained findings suggest that measurements of hyoid bone can be used for sex estimation in the Turkish population.     

Sex determination from the acetabulum: test of a possible non-population-specific discriminant function equation

In a recent study of pelvic dimorphism, Steyn and Patriquin¹ demonstrated that sex classification accuracies for a combined sample of South African blacks, South African whites, and Greeks living on Crete, differed very little from those obtained separately for the three groups. These results suggest that population-specific formulae may be unnecessary when using pelvic dimensions to discriminate sex, and according to the authors, the formulae derived in their study from a large and ethnically diverse sample should provide reliable standards for determining sex in a variety of populations. The purpose of the present study was to assess the accuracy of the discriminant function equation for acetabular diameter published by the aforementioned authors on a documented skeletal sample from France. The overall allocation accuracy obtained utilizing the pooled-group equation (84.1%) did not differ appreciably from that achieved using a sample-specific formula developed from the French dataset employed in this study (85.4%). This result is of practical importance to forensic anthropologists working in France, and elsewhere, particularly in situations where there is some question as to the population affinity of the skeletal remains. Future studies should continue to combine pelvic and non-pelvic data from disparate populations, to develop additional osteometric standards for discriminating sex with high accuracy across human groups.     

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.     

Biometric sex assessment from the femur and tibia in a modern Greek population

Forensic anthropologists assess sex by analysing quantitative and qualitative characters of the human skeleton. In general, the pelvis and skull are the skeletal regions used most often, but in many cases, they are missing or fragmentary. In such circumstances, where only limb bones are present, it is necessary to use techniques based on other skeletal elements. Metric traits of the long bones of the lower extremities have been reported as reliable indicators of sex. This study was designed to determine whether the two main long bones of the leg, the femur and tibia, can be used for the assessment of sex on a Greek skeletal population. The skeletal sample used in this study comes from the modern human skeletal collection that is currently housed at the National and Kapodistrian University of Athens and is known as The Athens Collection. It consists of 371 femora and 372 tibiae corresponding to 200 adult individuals (111 males and 89 females). The age range is 19–96 years for males and 20–99 years for females. The maximum lengths and epiphyseal widths were measured for the present study, and it was found that the discriminant analysis of the metrical data of each long bone provided high sex discrimination accuracies. The rate of correct sex discrimination based on different long bones ranged from 91.50 % (left femur) to 93.40 % (left tibia). Our results suggest that lower limb bones can be used effectively for sexing in forensic contexts, in addition to other sex assessment techniques.     

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.