Variability of footprint ridge density and its use in estimation of sex in forensic examinations

Abstract

The present study deals with a comparatively new biometric parameter of footprints called footprint ridge density. The study attempts to evaluate sex-dependent variations in ridge density in different areas of the footprint and its usefulness in discriminating sex in the young adult population of north India. The sample for the study consisted of 160 young adults (121 females) from north India. The left and right footprints were taken from each subject according to the standard procedures. The footprints were analysed using a 5 mm × 5 mm square and the ridge density was calculated in four different well-defined areas of the footprints. These were: F1 - the great toe on its proximal and medial side; F2 - the medial ball of the footprint, below the triradius (the triradius is a Y-shaped group of ridges on finger balls, palms and soles which forms the basis of ridge counting in identification); F3 - the lateral ball of the footprint, towards the most lateral part; and F4 - the heel in its central part where the maximum breadth at heel is cut by a perpendicular line drawn from the most posterior point on heel. This value represents the number of ridges in a 25 mm(2) area and reflects the ridge density value. Ridge densities analysed on different areas of footprints were compared with each other using the Friedman test for related samples. The total footprint ridge density was calculated as the sum of the ridge density in the four areas of footprints included in the study (F1 + F2 + F3 + F4). The results show that the mean footprint ridge density was higher in females than males in all the designated areas of the footprints. The sex differences in footprint ridge density were observed to be statistically significant in the analysed areas of the footprint, except for the heel region of the left footprint. The total footprint ridge density was also observed to be significantly higher among females than males. A statistically significant correlation is shown in the ridge densities among most areas of both left and right sides. Based on receiver operating characteristic (ROC) curve analysis, the sexing potential of footprint ridge density was observed to be considerably higher on the right side. The sexing potential for the four areas ranged between 69.2% and 85.3% on the right side, and between 59.2% and 69.6% on the left side. ROC analysis of the total footprint ridge density shows that the sexing potential of the right and left footprint was 91.5% and 77.7% respectively. The study concludes that footprint ridge density can be utilised in the determination of sex as a supportive parameter. The findings of the study should be utilised only on the north Indian population and may not be internationally generalisable.

Gender Determination from Toe Prints Among Kagay-Anons of Philippines for Forensic Application

“…The present study shows the mean ridge density of great toe for female (R: 10.20, L:10.49) is comparatively higher than male (R: 9.98, L: 10.82). While study on great toe ridge density among North Indian population from Himanchal Pradesh State showed the mean ridge density in female (R: 8.1, L: 7.7) to be higher than male (R:6.4, L:7.0) 21 . Another toe print study was conducted onIban population in Malaysia Borneo showed that the mean ridge density of great toe for males (R: 12.6, L:12.9) are comparatively lower than females (R:13.5, L:13.4) 24 .…”

“…Literature review shows that many studies have been conducted on fi ngerprint [17][18] and palm print [19][20] ridge density for gender determination, but there are limited study conducted on the footprint [21][22][23] and toe printridge density 4,24 . In most of the crime scenes, partial footprints are commonly found rather than complete footprint.…”

Sexing white 2D footprints using convolutional neural networks

“…The results obtained from the automated black-white percentage were better but still relatively poor. Ridge counting for each sampled image square followed the procedure of Krishan et al [ 25 ] and [ 26 ] was then used as a further test. Using the data for 168 participants, 29 footprints were excluded due to being faint, an average total ridge count for females were obtained of 52 versus 47 for males across the three squares.…”

Emergence of forensic podiatry—A novel sub-discipline of forensic sciences

“…The sexing from footprint ridge density is based upon the fact that the females possess finer ridge details than males and hence, the females have more ridges than the males in a defined area of a footprint. In this regard, only two studies [100,101] are available on sexing from footprint ridge density which show a sexing potential of about 82.6-83.6% and 77.7-91.5%, respectively.…”