Study on Sex Differences in Fingerprint Ridge Density of Patent Thumbprints by Ink Staining Method in Young Adult Indian Tamil Population

Abstract

The present study was conducted at the Forensic Medicine Department, Velammal Medical College Hospital & Research Institute, Tamil Nadu, India, with an objective to assess sex differences in thumbprint ridge density from patent thumbprints by ink staining method. One hundred and thirty three Tamil speaking medical students, 19-21 years of age, participated in the study after obtaining their informed consent. Sample size was calculated using Sample Size Calculator presented as a public service of Creative Research Systems: Survey software, ‘The Survey System’. In the present study, loop pattern was found in 56% of thumbprints, whorl pattern in 32.7%, arch in 8.7% and composite pattern was found in 2.6% of thumbprints. Thumbprint ridge density ranged from 8-12 ridges/25 mm2 in males and 10-14 ridges/25 mm2 in females. Difference in ridge density of left and right thumbprints was not significant (pvalue 0.8754). Difference in ridge density of fingerprint patterns was also not significant at p < 0.05. The present study results will be beneficial for law enforcement authorities in identifying gender from thumbprints. Sex difference in thumbprint ridge density was significant at p < 0.05 and it was inferred that ridge density of ≤10 ridges/25 mm2 is male and ≥11 is female.