法医学研究ジャーナル

A Case of Three Deltas in a Fingerprint

Abstract

Singh RK, Sharma M, Tarannum A, Pet-Paul W, Bernard L

Fingerprints begin forming at about the 6th to the 13th week of gestation. A number of factors determine the print pattern in the womb, including the density of the amniotic fluid surrounding the foetus, the size of the foetus, the friction in the womb, the location in the womb amongst others. Once developed the pattern remains constant throughout life. Basically there are three main patterns; The Loop, which rise up and loop back around, continuing on the same direction it started from and it accounts for about 70% of all fingerprints, Arches look like waves that rise and fall on the same fingerprint pattern, accounting for 5% whiles the Whorls appear as circular patterns accounting for 25%. The loop has only one delta, the Arch no delta with the Whorl pattern having two deltas. In the case presented here, a young man of 30 years, who is physically fit and normal without any significant clinical condition apart from a developmental defect of the right thumb which makes it different from the left thumb. From the ten fingerprint patterns taken with the aid of a scanner from the subject, only the abnormal right thumb of the subject with a whorl fingerprint pattern has three deltas which are extremely uncommon and quite different to the traditional, widely known two deltas seen in all whorl patterns in fingerprints. Fingerprint deltas are only present in loops and whorls. There are basically four types of fingerprint whorls. The plain with two deltas, central pocket with two deltas, the double loop whorls with two deltas and accidental whorls which have two or more deltas. Theoretically, less than 1 in 1000 people has these extremely rare fingerprints. The three deltas in a fingerprint whorl pattern may exist in accidental whorls, but no mention is made of it in plain whorls which make this case perhaps the first ever of a known plain whorl with three deltas. This feature is very uncommon in normal patterns. In this case the thumb of this young man has developed abnormally in the womb and has a whorl pattern with three deltas. It is imperative this pattern is taken into consideration when evaluating or interpreting fingerprints. Though the number may be statistically small, it is still essential this is taken into account in manual and especially when using automatic fingerprint identification software to evaluate known and unknown fingerprints.