THE BASIC fundamentals in the science of fingerprint identification are permanence and individuality.
PERMANENCE
Fingerprint ridges are formed during the third to fourth month of foetal development. These ridges consist of individual characteristics called ridge endings, bifurcations, dots and many ridge shape variances. The unit relationship of individual characteristics does not naturally change throughout life ... until decomposition after death. After formation, an infant's growing fingerprint ridges are much like drawing a face on a balloon with a ball-point pen and then inflating the balloon to see the same face expand uniformly in all directions. Unnatural changes to fingerprint ridges include deep cuts or injuries penetrating all layers of the epidermis and some diseases such as leprosy.
INDIVIDUALITY
In the over 140 years that fingerprints have been routinely compared worldwide, no two areas of friction skin on any two persons (including identical twins) have been found to contain the same individual characteristics in the same unit relationship.
This means that in general, any area of friction skin that you can cover with a dime (and often with just a pencil eraser) on your fingers, palms, or soles of your feet will contain sufficient individual characteristics in a unique unit relationship to enable positive identification to the absolute exclusion of any other person on earth.
Recent studies comparing the fingerprints of cloned monkeys showed that they, just like identical twin humans, have completely different fingerprints. When doctors state that twins have the same fingerprints, they are referring to the class characteristics of the general ridge flow, called the fingerprint pattern. These loop, arch and whorl ridge flow patterns have nothing to do with the individual characteristics used to positively identify persons. Before modern computerised systems, fingerprint classification was essential to enable manual filing and retrieval of fingerprints in large repositories.
