A comparative study of characteristic features of sweat pores of finger bulbs in individuals

Background: Fingerprints are the impressions left on any material by the volar surface also called finger bulbs of the fingers. As per the law of individuality, each individual has a unique set of tiny raised ridges or friction ridges that have been considered necessary in individualization in forensic work. Friction ridges over their surfaces bear the small openings known as sweat pores. The latter are connected to ducts of sweat glands. These pores are also unique to each individual as per many studies and vary in their shape, size, location, and frequency over the friction ridges. Poroscopy is a method of personal identification in which the characteristics of sweat pores on the friction ridge impression of palmar and plantar surfaces are examined. The present study aimed to uncover the similarities in the sweat pores present on the friction ridges of an individual in respect to their position ‘middle or periphery’ and to their frequency per unit length and per unit area. Materials and methods: A total number of 50 samples were collected randomly from different male individuals (graduate and postgraduate students at Amity University). Rolled fingerprint impressions were collected on FBI fingerprint cards. The collected samples were then analyzed through a stereo-microscope and photomicrography for the shape, position, and the number of sweat pores on the friction ridges per unit length and per unit area. Besides, the number of pores present on three different fingers ‘Thumb, Index, Ring’ of an individual were considered for this study. Results: Our results report that no relationship exists between the position and frequency of sweat pores occurring per unit length and per unit area. However, a significant correlation exists between the number of pores per unit length and per unit area of the Thumb and Ring fingers for the middle position. Also, a significant correlation was observed between the number of pores per unit length and per unit area of the Index and Ring fingers for the periphery position. Conclusions: This study may provide useful information about sweat pores present on friction ridges and their utilization for personal identification up to an extent in the cases where very few ridges will be encountered on the crime scene. These data can further be used in forensic research involving individual identification from poroscopy.