Use of 2D:4D digit ratios to determine sex

Gender Determination Using Index and Ring Finger Linear Measurements in North Indian Population: A Cross-Sectional Study

BACKGROUND

In the fields of medico-legal matters and bio-archaeological settings, gender evaluation plays a pivotal role in the initial stages of human identification. Approximately half of the population at risk is excluded when gender is determined, making it the most essential factor for identification. When it comes to medico-legal matters and bio-archaeological settings, gender evaluation is a crucial initial step in human identification. Traditional gender determination procedures, such as skull and pelvic analysis, may be hindered by fragmentary human remains that have been degraded by various forms of inhumation or physical assaults.

AIM

To investigate sexual dimorphism, this study examined the ratio of index finger length to ring finger length.

MATERIALS AND METHOD

The lengths of the index and ring fingers were measured and the ratios between them were calculated for both hands separately. Applications of IBM SPSS Statistics for Windows, Version 16.0 (Released 2007; IBM Corp., Armonk, New York, United States) included Student's t-test and Levene's test.

RESULTS

According to the study, women's index finger-to-ring finger length ratios were much longer than men's. The ratio of index finger to ring finger length was significantly different between the sexes on both sides of the hand (p<0.001). In terms of the right hand, the threshold value was 0.9666 for men and 0.9952 for females, while in terms of the left hand, the values were 0.9638 and 0.9920, respectively.

CONCLUSION

With an advancing front in this arena on gender determination, the use of digits has become an additional source of support to physical anthropologists for bio-archaeological surveys and to forensic experts for use in medico-legal investigations for fragmentary remains received during investigatory trials.

Beyond Human Perception: Sexual Dimorphism in Hand and Wrist Radiographs Is Discernible by a Deep Learning Model

Despite the well-established impact of sex and sex hormones on bone structure and density, there has been limited description of sexual dimorphism in the hand and wrist in the literature. We developed a deep convolutional neural network (CNN) model to predict sex based on hand radiographs of children and adults aged between 5 and 70 years. Of the 1531 radiographs tested, the algorithm predicted sex correctly in 95.9% (κ = 0.92) of the cases. Two human radiologists achieved 58% (κ = 0.15) and 46% (κ = − 0.07) accuracy. The class activation maps (CAM) showed that the model mostly focused on the 2nd and 3rd metacarpal base or thumb sesamoid in women, and distal radioulnar joint, distal radial physis and epiphysis, or 3rd metacarpophalangeal joint in men. The radiologists reviewed 70 cases (35 females and 35 males) labeled with sex along with heat maps generated by CAM, but they could not find any patterns that distinguish the two sexes. A small sample of patients (n = 44) with sexual developmental disorders or transgender identity was selected for a preliminary exploration of application of the model. The model prediction agreed with phenotypic sex in only 77.8% (κ = 0.54) of these cases. To the best of our knowledge, this is the first study that demonstrated a machine learning model to perform a task in which human experts could not fulfill.

Index/Ring Finger Ratio, Hand and Foot Index: Gender Estimation Tools

INTRODUCTION

Gender estimation from dismembered human body parts and skeletal remains in cases of mass disasters, explosions, and assaults cases is an imperative element of any medico-legal investigations and has been a major challenge for forensic scientists.

AIM

The aim of the present study was to estimate the gender by using index and ring finger length ratio, hand and foot index along with the correlation of both the hand and foot index to determine the vital role of all the indices in establishing gender identity.

MATERIALS AND METHODS

A descriptive cross-sectional study was done on 300 subjects (150 males and 150 females). Various anthropometric measurements like hand length, hand breadth and hand index, Index Finger Length (IFL), Ring Finger Length (RFL) and IFL/RFL ratio as well as foot length, foot breadth and foot index were estimated in millimeters (mm) with the help of sliding-anthropometric caliper. The data was analysed using independent t-test and Pearson correlation coefficient test. A probability value (p) of ≤ 0.05 was considered statistically significant.

RESULTS

The index and ring finger ratio was found to be higher in females as compared to males. The hand and foot index was more in males than in females. The index and ring finger length ratio, hand and foot index between males and females was found to be statistically significant for both hands and feet. A statistically significant correlation was determined between hand indexes versus foot index.

CONCLUSION

This study can be useful to establish the gender of a dismembered hand or foot when subjected for medicolegal examination.

Digit ratio (2D:4D): Is it possible to use it for sex determination in the study of human skeletal remains?

OBJECTIVES

Sexual dimorphism in the relative length of the second-to-fourth digits (the digit ratio, or 2D:4D) in humans has been reported in many studies. The aim of our study was to ascertain possibility of using the 2D:4D ratio as an additional marker for sex determination in the study of human skeletal remains.

METHODS

We have studied 2D:4D ratios obtained from measurements of finger phalanges and metacarpal bones in Russian (45 adult males and 26 adult females) and German (58 adult males and 29 adult females) skeletal series.

RESULTS

The difference in 2D:4D ratio between the male and female subsamples in both skeletal series was not statistically significant. Analysis of variance revealed that the 2D:4D ratios in our sample varied more by ethnicity than by the sexual identity of the skeletal material.

CONCLUSION

Our results suggest that the 2D:4D ratio cannot be used as an appropriate trait for the sex determination of human skeletal remains. Am. J. Hum. Biol. 28:591-593, 2016. © 2015 Wiley Periodicals, Inc.

Sexual dimorphism in finger length ratios and sex determination - A study in Indo-Mauritian population

Many studies have shown that the finger length ratios might be characteristic for sexual dimorphism. The aim of the study was to determine sexual dimorphism in finger length ratios among the representatives of the Indo-Mauritian population. The study group comprised of 200 healthy Indo-Mauritian people (100 male and 100 female) of the age ranged from 19 to 25 years. The lengths of second (2D), third (3D), forth (4D) and fifth (5D) finger of both hands were measured by using a vernier caliper. Our results indicate that all finger length ratios have significant sex differences (p-value < 0.05) except 2D:5D and 3D:5D. To conclude, 2D:4D ratio is the most decisive ratio (predictive accuracy = 0.61) which can demarcate between male and female.

Measurement standards for human metacarpals

Standards for measuring the metacarpals are absent from commonly used osteometric guides. Perhaps the closest to a set of standard measurements in common use today are those proposed by Scheuer and Elkington (Scheuer and Elkington: J Forensic Sci 38 (1993) 769-788) for forensic sex assessment. They include caliper measurements of interarticular length, base and head width, base and head height, and maximum midshaft diameter. Over the last decade, a new set of measurements that encompass similar dimensions to those used by Scheuer and Elkington, but which are taken with a mini-osteometric board (MOB) have been developed by the lead author. Use of the MOB avoids the need to manipulate both the bone and calipers in three-dimensional space and causes less strain on the hands. However, the question of intra- and interobserver accuracy has not been adequately addressed for either set of measurements. The purpose of this study was to test both the Scheuer/Elkington and MOB measurements on 20 hands from 10 anatomical skeletons for intra- and inter-observer accuracy. The study found that 92% of the MOB measures had a lower intraobserver error, and 88% had a lower interobserver error than did the caliper measurements. It also found that the maximum midshaft diameter measurement used by Scheuer and Elkington is more repeatable than a mediolateral diameter. Overall, 88% of the 25 MOB measurements had median intraobserver error rates of under 1.5%, compared with 60% of the caliper measurements. Furthermore, the MOB measurements as a set were taken 10 to 12% faster than the caliper measurements.