Distribution of the minutiae in palmprints: Topological and sexual variability

Study of the fingerprints of a Spanish sample for the determination of the hand and finger

The individuality and permanence of fingerprints make of them a very useful feature in the identification of individuals. There are now automated computer programmes that allow a quick comparison between a fingermark and a database. However, in order to assess the strength of evidence in fingerprint identification, complementary information on the frequencies of the different morphological features of the dermopapillary ridges is required. This idea is used in this work as a starting point to evaluate the frequencies of the parameters used in the determination of the hand and finger in a large sample of 2600 fingerprints taken from 134 male and 127 female Spanish population. Based on these fingerprints, the frequencies of different categories of the following parameters were obtained: type of pattern, slope of the apex ridge, subtype of two-delta pattern, ridge tracing, major angle, major ridge count, bisector, rotation of the central ridge, assimilation to loops and slant. Moreover, the results have shown that these characters are useful for the determination of the hand in whorls (two-delta pattern) and loops (one-delta pattern), but not for the determination of the finger. The most useful and classificatory parameter when determining the hand of origin of a two-delta fingerprint is the slope of the apex ridge, and for the one-delta pattern, knowing the location of the delta allows the correct estimation of the hand of a fingerprint in more than 93% of the cases. The data presented in this paper are novel and can be used by latent print examiners to improve the statistical basis of their decisions in reaching conclusions.

Distribution of different minutiae in thumbprint and its application to determine sex distinctions

Background

The present study is an attempt to explore the distribution of different minutiae in two topological areas of thumbprint and its application to determine sex distinctions.

Methods

For this purpose, a sample of 100 subjects (50 males and 50 females) ranging in age from 18 years to 25 years were taken from the Shimla (North India). A modified standardized method was adopted to count and classify 20 different types of minutiae.

Results

Findings of the study indicated that the frequency of thumbprint minutiae was higher among males than their female counterparts. Ridge endings were the most frequently occurring minutiae followed by bifurcation and convergence in both the sexes. No M-B was noticed among female participant, while negligible percentage (0.04%) of males exhibited M-B. The mean values of most of the minutiae were found to be higher in the outer circle than inner circle of the thumbprint in both the sexes. Lower frequency of ridge ending (< 20 for right hand and 31–40 for both right and left hand), convergence (< 10 for both right and left hand), and bifurcation (< 10 and 31–40 for right hand and < 20 for left hand) have higher probability of female origin. While higher frequency of ridge ending (> 60 for right hand and > 50 for left hand), convergence (> 20 for both right and left hand) and bifurcation (> 40 for right hand and > 30 for left hand) was more likely of male origin.

Conclusions

Findings of present study identified sex distinction in the distribution of minutiae with respect to the topological areas on the thumbprint.