The image shown is of a finger-print
Dactylography / Dermatoglyphics / Finger prints
- It is the study of epidermal ridges and their configurations.
- Finger prints are present from birth both on epidermis and dermis, remain constant through out life and can’t be altered without destroying true skin.
- Ridge pattern of fingerprints appears as early as 12 weeks of IUL and is completed by 24 weeks.
- Finger print pattern is absolutely individual i.e. no two hands are entirely alike, not even identical twins. That’s why, it is best (most sensitive and most specific) and most reliable method of identification (Quetelet’s rule of biological variation).
- DNA finger printing may be same in monozygotic twins.
- The pattern is neither inherited nor identical in any two persons. So the paternity cannot be proved through finger print patterns. However, paternity can be proved by DNA finger printing.
- Loops (67% most common) > whorls (25%) > arches (7%) > composite (2% least common) are four main types of pattern.
- Final identification is made based on the comparison of characteristics like – ridge endings, bifurcations, lake formation, broken ridges, short ridges etc.
It is accepted that chances of 2 finger prints matching 16 ridge characteristic are infinitely small (Parikh’s).
In practice 8 – 16 (Reddy) / 16 – 20 (Seth, Simpson) points of fine comparision are accepted as proof of identity.
To make a positive identification with the help of a partial finger print, the points of similarity should be at least 16.
- Permanent impairment of fingerprints occurs in:
Leprosy, Electric injury, Radiation exposure, Skin grafting.