Sex Determination of Human Remains Using Fingerprint Ridge Density.

Abstract

Fingerprint ridge density (FPRD) refers to the number of ridges within a defined area of a fingerprint. It is known to exhibit sexual dimorphism, with females generally showing finer (more densely packed) ridges than males. This cross-sectional observational study was conducted to evaluate the sexual dimorphism of FPRD and its applicability in mass casualty scenarios, where only hand or finger remains may be available for identification. Fingerprints were collected from 429 male and 50 female cadavers subjected to postmortem examination at our tertiary care institute located in the Northwest part of India from July 2016 to December 2017, by ink-impression on paper. Epidermal ridge counts were obtained within a 5 × 5 mm square area on the radial side of each fingerprint (adjacent to the core), following the method of Acree. Ridges crossing a diagonal line within the square were counted under magnification to calculate ridge density (ridges/25 mm²). Statistical analysis (including Student's t-test) was performed to compare male and female ridge density distributions. Female fingerprints showed significantly higher ridge densities than male fingerprints (mean FPRD ≈ 14.86 in females vs. 12.18 in males, p<0.001). No male fingerprint had a ridge density above 14 ridges/25 mm² and no female had below 12, yielding a practical threshold for sex differentiation. Combining all ten fingers improved accuracy: ridge counts among 10-13 indicated male origin, whereas 14-16 indicated female origin in ~99.0% of cases. The FPRD method provides a quick, cost-effective means of sex determination from fragmented remains. In disaster victim identification, a simple ridge count in a defined fingerprint area can reliably distinguish sex on the spot, aiding forensic and humanitarian efforts when DNA or other analyses are impractical.