To make a positive identification with the help of an identification feature shown in the picture below, the points of similarity should be at least?
The image shown is of a finger-print
Dactylography / Dermatoglyphics / Finger prints
- It is the study of epidermal ridges and their configurations.
- Fingerprints are present from birth both on epidermis and dermis, remain constant throughout life, and can’t be altered without destroying true skin.
- The Ridge pattern of fingerprints appears as early as 12 weeks of IUL and is completed by 24 weeks.
- Fingerprint 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 fingerprinting may be the same in monozygotic twins.
- The pattern is neither inherited nor identical in any two persons. So the paternity cannot be proved through fingerprint 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 fingerprints matching 16 ridge characteristics 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 fingerprint, the points of similarity should be at least 16.
- Permanent impairment of fingerprints occurs in:
Leprosy, Electric injury, Radiation exposure, Skin grafting.