Thursday, February 20, 2014

Fingerprints

Fingerprints In the minds of many people, fingerprints are significant only for the identification of criminals . But the skin corrugations that produce fingerprints are a functionally important part of the structure of the finger pads, not only in human beings, but also in a number of other mammals, especially primates, whichuse prehensile hands (and feet ) foractive exploration of surfaces and for the fine manipulation of objects.

Fingerprints form naturally during the development of the human fetus, starting about 13 weeks after conception. The inner surfaces of the fingers and the palms of the hands, which are covered with hairless (glabrous ) skin develop tiny ‘pods’, which are the precursors of the pores of sweat glands. These pods, or ridge units, expand and coalesce with neighbouring pods, producing roughly linear ridges, with the sweat pores distributed along their crests, raised above the surface of the surrounding skin.

These form the familiar parallel and swirling ridges and intervening furrows, the exact pattern of which is determined by complex, irregular stresses in the skin. They can be seen not only on the pads of the fingers and thumb, but over much of the glabrous skin on the undersurface of fingers and toes, and on the palms and soles of the hands and feet. (A little talcum powder dusted over the surface of the skin makes the pattern more easily visible.)

Post By : Syeda Kulsum Ali.

No comments:

Post a Comment