Study of Fingerprints Ridge Density and Its Reliability in Sex Determination in a Sample of Sohag Population

Fingerprint identification is the first simple individual identification before using complicated techniques such as DNA analysis. Identification of sex plays a vital role in medicolegal investigations. The aim of the present study was to find out sex differences based on fingerprint ridge density and its possible applicability in determination of sex in forensic medicine. The present study was conducted on 300 students (150 males and 150 females) in faculty of Medicine, Sohag University. For collection of fingerprints, plates uniformly smeared with thin layer of black printer ink were prepared. Subjects were asked to apply their fingers on the smeared plate and then transferred to the prepared fingerprint card. Epidermal ridges of both men and women were counted within a square of 5 mm * 5 mm drawn on a transparent film fixed to a lens. The results revealed that the mean values of the number of fingerprint ridges in females in the right and left hands was 17.73 ± 1.69 and 17.74 ± 1.73 respectively. The mean value of fingerprint ridges of both hands were 17.74 ± 1.63. The mean values of fingerprint ridges of the right and left hands in males was 14.82 ± 1.52  and 15.22 ± 1.32  respectively. The mean value of fingerprint ridges of both hands were 15.02 ± 1.33. Analysis of Receiver Operating Curve results showed that the mean of right finger ridges of 15.9 is the most accurate cut point to differentiate females from males. Meanwhile the mean of 16.3 ridges is the most accurate cut point for the left fingers. The present study revealed that females have a statistically significant ridge density more than males. The mean ridge densities can be used as a presumptive indicator of sex of an unknown print left at the crime scene.