Unusual fingerprint patterns in humans: implications for forensic casework and fingerprint research

The tenacity of the fingerprint evidence for the identification of criminals has been well documented, but none of the research work so far focussed on unusual prints. Therefore, in the present study, we attempted to define rarely encountered fingerprints in a human population. Our purpose was to explore unusual pattern types on the finger balls and compare these with commonly occurring and classifiable pattern types. Furthermore, we discuss the occurrence of unusual fingerprints in both the sexes with reference to the finger digits. The study was conducted on 512 participants aged between 18 and 35 years from two ethnic groups of North India. A total of 5120 fingerprints from each digit of the 512 individuals were obtained. The fingerprints were analysed for the pattern types based on Henry's classification. Patterns that did not fall in the prescribed category as per the definition of the published finger pattern types were identified as unusual fingerprints. We found an incidence of unusual prints of 0.21% and describe these based on a comparison with the general pattern types according to Henry's classification. We describe eleven unusual fingerprint patterns, formulating categories that may aid in the individualisation process. The proposed new nomenclature of these unusual fingerprints may assist forensic scientists and fingerprint examiners in better understanding and labelling of similar patterns in forensic cases. Our research may also influence the general forensic science community and biological anthropologists in making population standards pertaining to different types of fingerprints in various population groups and their genetic and familial relationships.