A fingerprint is an impression of the friction ridges of all or any part of the finger. A friction ridge is a raised portion of the epidermis on the pal mar (palm and fingers) or plantar (sole and toes) skin, consisting of one or more connected ridge units of friction ridge skin. These ridges are sometimes known as â€œdermal ridges â€œor â€œdermal papillaeâ€™.
Fingerprint may be deposited in natural secretions from the eccrine glands present in friction ridge skin (secretions consisting primarily of water) or they may be made by ink or other contaminants transferred from the peaks of friction skin ridges to a relatively smooth surface such as a fingerprint card. The term fingerprint normally refers to impressions transferred from the pad on the last joint of fingers and thumbs, through fingerprint cards also typically record portions of lower joint areas of the fingers.
Today fingerprint devices are by far the most popular form of biometric security used, with a variety of systems on the market intended for general and mass-market usage. Long gone are the huge bulky fingerprint scanners; now a fingerprint-scanning device can be small enough to be incorporated into a laptop for security.