Sex estimation from foot dimensions in an indigenous Indian population

Dismembered/severed human remains are frequently found in cases of mass disasters and criminal mutilation. Sex estimation from foot dimensions, therefore, has a vital role in establishing personal identity. There is a paucity of literature on this issue from various Indian populations. The "Rajbanshi" is one such indigenous population located in the state of West Bengal, India. The present study attempts to estimate sex from foot length, foot breadth, and foot index among 350 living adult Rajbanshi (175 men and 175 women) individuals (age range: 18-50 years). The study concludes that foot dimensions show significant sex differences. Both sectioning point and regression analyses can be used to estimate sex from foot dimensions. However, multiple regression models appear to have the maximum accuracy in sex differentiation. Although statistically significant sex differences are evident for foot index, its practical utility appears to be limited because of considerable overlap.     

Sex determination from hand and foot bone lengths

Numerous studies have addressed sex estimation from the hands and feet with varying results. These studies have utilized multiple measurements to determine sex from the hands and feet, including measures of robusticity (e.g., base width and midshaft diameter). However, robusticity measurements are affected by activity, which can disguise underlying patterns of sexual dimorphism. The purpose of this study is to investigate the utility of length measurements of the hands and feet to estimate sex. The sample consists of white females (n=123) and males (n=136) from the Terry Collection. Discriminant function analysis was used to classify individuals by sex. The left hand outperformed both the right hand and foot producing correct classification rates exceeding 80%. Surprisingly, the phalanges were better sex discriminators than either the metacarpals or metatarsals. This study suggests that length measures are more appropriate than robusticity measures for sex estimation.     

Sex Determination from Hand Dimensions of North and South Indians

Abstract:  When dismembered human remains are encountered, the decedent's sex may not be obvious. For these scenarios, techniques for sex determination may play a vital part of the medicolegal investigation. Five hundred hands (230 males, 270 females) from North and South Indian region were studied to investigate sexual dimorphism in hand dimensions (hand length, hand breadth, and palm length). The hand index (hand breadth/hand length × 100) and the palm index (hand breadth/palm length × 100) were derived. The hand dimensions show a higher accuracy in sex determination when compared to indices. Of all hand dimensions, hand breadth has the highest accuracy of sex determination in the study group. The sex differences were found to be statistically significant only for the hand index on the left side. The morphometric parameters of the hand show considerable sexual dimorphism in the Indian population while the hand and palm index remain poor sex indicators. The study thus has medicolegal implications when a dismembered hand is brought for examination.     

Heel-ball (HB) index: sexual dimorphism of a new index from foot dimensions

The present research is aimed to introduce Heel-ball (HB) index from foot dimensions and determine whether this index exhibits sexual dimorphism. The study was conducted on a sample of 303 North Indian individuals (154 men, and 149 women) aged between 13 and 18 years. The stature, body weight, foot breadth at the ball (BBAL), and foot breadth at heel (BHEL) were measured. The HB index was derived by the formula BHEL × 100/BBAL. Although the mean HB index was larger in women in both feet it showed statistically significant sex differences in the right foot only. The study shows that while the foot dimensions show a positive correlation with stature and weight, the HB index is independent of the stature and weight of an individual. This novel index (HB index) may be utilized in sex determination when a part of the foot is brought for medico-legal investigation.     

Sex discrimination potential of buccolingual and mesiodistal tooth dimensions

Abstract:  Tooth crown dimensions are reasonably accurate predictors of sex and are useful adjuncts in sex assessment. This study explores the utility of buccolingual (BL) and mesiodistal (MD) measurements in sex differentiation when used independently. BL and MD measurements of 28 teeth (third molars excluded) were obtained from a group of 53 Nepalese subjects (22 women and 31 men) aged 19–28 years. Stepwise discriminant analyses were undertaken separately for both types of tooth crown variables and their accuracy in sex classification compared with one another. MD dimensions had recognizably greater accuracy (77.4–83%) in sex identification than BL measurements (62.3–64.2%)—results that are consistent with previous reports. However, the accuracy of MD variables is not high enough to warrant their exclusive use in odontometric sex assessment—higher accuracy levels have been obtained when both types of dimensions were used concurrently, implying that BL variables contribute to sex assessment to some extent. Hence, it is inferred that optimal results in dental sex assessment are obtained when both MD and BL variables are used together.     

Sex determination using nonmetric characteristics of the mandible in Koreans

The mandible is the largest and hardest facial bone and retains its shape better than other bones in the forensic and physical anthropologic field. The mandible can be used to distinguish among ethnic groups and between sexes. We examined the morphological characteristics of the mandibles of 102 Koreans of either sex. Of 13 nonmetric items of the mandible, the characteristic that best allowed the sexes to be distinguished was the contour of the lower border of the mandible: rocker-shaped mandibles predominated in males (68.1%), whereas most females (84.6%) exhibited a straight mandible. In addition, the mental region was shaped differently between the sexes: the shape of the chin in most males was generally bilobate or square (91.7%), whereas the chin in females was either square (45.5%) or pointed (54.5%). In this study, the positive predict values of male and female were 92.5% and 73.7%, respectively. Therefore, the nonmetric method used to analyze the mandible in this study can be used for sex discrimination.     

Stature Estimation from Foot Length Using Universal Regression Formula in a North Indian Population

Abstract:  Stature is a significant parameter in establishing identity of an unknown. Conventionally, researchers derive regression formula separately for males and females. Sex, however, may not always be determined accurately, particularly in dismembered remains and thus the need for a universal regression formula for stature estimation irrespective of sex of an individual. The study was carried out in an endogamous group of North India to compare the accuracy of sex-specific regression models for stature estimation from foot length with the models derived when the sex was presumed as unknown. The study reveals that regression equation derived for the latter can estimate stature with reasonable accuracy. Thus, stature can be estimated accurately from foot length by regression analysis even when sex remains unknown.     

Metacarpal sexual determination in a Spanish population

Anthropologists and forensic pathologist determine the sex of skeletons by analyzing quantitative and qualitative characters in the bone remains. Generally, the skull and os coxae are the elements most used, but they are not always preserved. In such cases, the investigator needs to have available other techniques based on different remains. The aim of the present work is to develop and describe discriminating functions for sex determination in a recent Spanish population using metacarpal morphology. A sample of bones corresponding to a contemporary Spanish population deposited at the Complutense University of Madrid (UCM) was analyzed. This sample comprised 697 metacarpals, corresponding to 79 adult individuals (37 men and 42 women). These allowed us to obtain 120 unifactorial discriminant functions. We selected the 10 equations, one for each metacarpal from both hands, that provided the best sexual discrimination. The correct sex classification rank progressed from 81%, for right (R) metacarpals IV and V, to 91%, for left (L) metacarpal II. The results suggest that metacarpals are structures that can be used for sex determination in paleoanthropological and forensic identifications.     

中国南方汉族人残碎股骨上端的性别判定

目的建立中国南方地区汉族人残碎股骨上端性别判别方法。方法对国内南方九省市的已知确切性别的100具股骨进行研究，测量股骨上端的7项指标，应用SPSS统计软件对数据进行分析，建立性别判别方程。结果7项指标中6项指标存在显著的性别差异，建立全指标及单指标的性别判别方程，判别率在59．6％～92．9％。结论建立的性别判别方程可以用于法医学实践。     

Development and Assessment of Postcranial Sex Estimation Methods for a Guatemalan Population

This study tests whether postcranial sex estimation methods generated from Hispanic, and mainly Mexican samples, can be successfully applied to other increasingly common migrant populations from Central America. We use a sample of postcranial data from a modern (1980s) Guatemalan Maya sample (n = 219). Results indicate a decrease in classification accuracies for previously established univariate methods when applied to the Guatemalan study sample, specifically for males whose accuracies ranged from 30 to 84%. This bias toward inaccuracies for Guatemalan males is associated with the smaller skeletal sizes for the Guatemalan sample as compared to the samples used in the tested sex estimation methods. In contrast, the tested multivariate discriminant function classification yielded less sex bias and improved classification accuracies ranging from 82 to 89%. Our results highlight which of the tested univariate and multivariate methods reach acceptable levels for accuracy for sex estimation of cases where the region of origin may include Guatemala.     

中国汉族人颅骨数字模型的性别判别方法

目的利用步进Fisher法建立多元性别判别函数,对西安地区成年人颅骨进行性别判别。方法从颅面数据库中选择西安地区133个（73男,60女）三维颅骨模型,利用计算机软件测量并统计颅骨的12项几何测量指标和2项角度测量指标,利用步进Fisher方法建立多元性别判别函数,并对方程进行回代检验。结果男性的12项几何测量指标均值大于女性,女性的2项角度测量指标均值大于男性,除2项指标（X7和X14）外,其他指标均存在显著性差异（P〈0.01）。由4项指标建立的判别方程,判别率男性为87.5%,女性为86.67%。结论利用计算机软件可以实现完整颅骨和无下颌的颅骨的性别判别。     

Testing Discriminant Functions for Sex Determination from Deciduous Teeth*,†

Abstract: Three studies have proposed discriminant functions for sex determination from deciduous tooth crown dimensions, and this study tests the existing functions on a sample of 46 Portuguese immature skeletons of known sex, aged from birth to 10 years. Deciduous teeth were measured in their mesiodistal and faciolingual crown dimensions, and percentage of correct allocation accuracy in determining sex using each specific function was determined. Discriminant functions were also calculated from data collected for this study and tested using cross‐validation. Results show poor overall accuracy (33.3–75%) and poor cross‐validation (46.2–60.0%). This is related to low sexual dimorphism in deciduous tooth crown size, as well as differences in degree of sexual dimorphism and in overall tooth size between different samples. For these reasons, deciduous crown size does not seem to show significant forensic value as discriminator of sex, particularly when methods developed on one population are applied to individuals of another population.     

Sex estimation in forensic anthropology: skull versus postcranial elements

When the pelvis is unavailable, the skull is widely considered the second best indicator of sex. The goals of this research are to provide an objective hierarchy of sexing effectiveness of cranial and postcranial elements and to test the widespread notion that the skull is superior to postcranial bones. We constructed both univariate and multivariate discriminant models using data from the Forensic Anthropology Data Bank. Discriminating effectiveness was assessed by cross-validated classification, and in the case of multivariate models, Mahalanobis D(2). The results clearly indicate that most postcranial elements outperform the skull in estimating sex. It is possible to correctly sex 88-90% of individuals with joint size, up to 94% with multivariate models of the postcranial bones. The best models for the cranium do not exceed 90%. We conclude that postcranial elements are to be preferred to the cranium for estimating sex when the pelvis is unavailable.     

Sex Determination from the Second Cervical Vertebra: A Test of Wescott’s Method on a Modern American Sample*

Abstract: Numerous methods for establishing a biological profile exist; however, many of these methods rely on the recovery of several specific bones or on fragile skeletal elements that are sometimes irrecoverable. It is for this reason new methods utilizing other previously under‐documented bones should be established and tested by the forensic anthropological community. This study tests the accuracy of Wescott’s (J Forensic Sci 2000;45(2)) method for determining sex from the second cervical vertebra. Specimens were drawn from the donated skeletal collection curated at the Hamilton County Forensic Center (n = 57) and the William M. Bass Donated Skeletal Collection (n = 243). Both intra‐ and inter‐observer error rates were low and accurate classifications ranged from 78% (females‐Function 1) to 90.6% (males‐Function 5). Of the five functions, Function 4 achieved the highest overall accuracy, with 260 individuals (86.7%) falling into the correct category. Overall, this method is an effective classificatory tool for sex estimation.     

Metric assessment of the "mastoid triangle" for sex determination: a validation study

Recently, a metric approach to skeletal sex determination was published by Paiva and Segre which is based on the summation of two triangular areas defined by three distinct craniometric landmarks: Porion, Mastoidale, and Asterion. According to the authors, values for the total triangle > or =1447.40 mm(2) are characteristic for male crania, while values < or =1260.36 mm(2) are indicative of female skulls (95% confidence). In order to evaluate the method's validity, two sex- and age-documented samples of different provenience were analyzed (N=197). The results show that while the indicated measurements display significant sex differences, the technique is of little practical meaning where a single individual must be independently classified. It is hypothesized that differences in the expression of sexual dimorphism as well as a population-specific variability of the asterion location undermine the value of the mastoid triangle as a sex determinant.     

Nonmetric sex determination from the distal and posterior humerus in black and white South Africans

The successful identification of human skeletal remains relies on proven diagnostic techniques for sex determination. This research utilized 608 individuals from South Africa (420 men, 188 women) to conduct a blind nonmetric determination of sex from three features of the distal humerus: olecranon fossa shape, angle of the medial epicondyle, and trochlear extension. A scoring system between males and females was implemented, and the aggregate score of the three features determined the estimated sex of the skeletal element in question. With all features combined, black and white South Africans were categorized successfully as either male or female 75.5% (77% accuracy rate for females, 74% accuracy rate for males). This classification rate is lower than what was found in previous studies, but suggests that characteristics of the distal humerus are still quite valuable when estimating skeletal sex. More research is needed to assess reasons for the differential expression of these traits in different populations and to determine whether the method is nonpopulation specific.     

Test of an alternative method for determining sex from the os coxae: applications for modern Americans

A recently proposed method for determining sex from the os coxae reports a 98% success rate using European collections. The purposes of the present study are to (1) evaluate the success rate of this proposed method using modern American os coxae from different population subgroups; (2) compare the success rate of the new method with that obtained using traditional techniques; and (3) determine replicability of the new method and interobserver error. Eight hundred and seventy-six adult left os coxae were independently evaluated by both authors. Summary statistics for sex classifications were calculated for the total sample and for a random sample of 400 individuals. The impact of sex and ancestry on the success of each method was calculated on the random sample using Pearson's chi2 values. Results demonstrate that for modern American os coxae, neither sex nor race have a significant impact on the success rate for either the new or traditional methods (p < 0.01). Additionally, the success rate of the new method is comparable with that obtained using traditional techniques. Finally, interobserver error using the new method for overall sex determination is low.     

Estimation of stature from hand impression: a nonconventional approach

Stature is used for constructing a biological profile that assists with the identification of an individual. So far, little attention has been paid to the fact that stature can be estimated from hand impressions left at scene of crime. The present study based on practical observations adopted a new methodology of measuring hand length from the depressed area between hypothenar and thenar region on the proximal surface of the palm. Stature and bilateral hand impressions were obtained from 503 men of central India. Seventeen dimensions of hand were measured on the impression. Linear regression equations derived showed hand length followed by palm length are best estimates of stature. Testing the practical utility of the suggested method on latent prints of 137 subjects, a statistically insignificant result was obtained when known and estimated stature derived from latent prints was compared. The suggested approach points to a strong possibility of its usage in crime scene investigation, albeit the fact that validation studies in real-life scenarios are performed.     

A Comparison of Palmar Dermatoglyphics in Two Ethnic Indian Populations of North Bengal,India*

Abstract: Dermatoglyphic print comparisons can be utilized to establish personal identification in forensic cases. The northern part of the state of West Bengal, India, is the home to many ethnic populations. Two such populations are the Rajbanshi and the Mech. Palm prints were collected from 192 adult Rajbanshi (105 men and 87 women) and 100 adult Mech (50 men and 50 women) individuals for print comparison using the standard ink and roll print method. The dermatoglyphic variables studied were mainline formulae, termination of mainline, positional variation of axial triradii, and true pattern of hypothenar and thenar configuration area. There were differences between the Rajbanshi and Mech individuals with respect to these dermatoglyphic variables. The uses of these variables appear to be limited only to ethnic identification, not personal identification. The present investigation further highlights the racial affinity, sex, and bilateral differences among Rajbanshi individuals using dermatoglyphic palmar variables.     

Use of 2D:4D Digit Ratios to Determine Sex

Second to fourth digit ratios (2D:4D) are sexually dimorphic in human hands and established by the 13th gestational week. Application of 2D:4D for determining sex in living individuals by Kanchan et al. (Forensic Sci Int, 181, 2008, 53.e1) produced classification rates of 80% for males and 74–78% for females. Few studies have explored the use of 2D:4D for sexing skeletal remains. We test estimated finger lengths, phalanx lengths, and 2D:4D derived from hand bones for determining sex. Maximum phalanx length was collected using a mini‐osteometric board from 451 individuals of known age, sex, and ancestry in four skeletal collections. Logistic regression of 2nd and 4th digit finger and phalanx lengths produced classification rates greater than 80%. Digit ratios, however, failed to reach classification rates greater than 59%. Our results support those of Voracek (Forensic Sci Int, 185, 2009, e29) and suggest that 2D:4D may be population‐specific and thus inappropriate for universal application as a means of determining sex.