Why do we have loops and whorls?

Loops and whorls - the skin's surface is marked by a series of fine lines and ridges which deepen with age. The pattern on the tips of the fingers is peculiar to each individual and is used as a means of identification. In fact the ridges of the skin on the lower finger joints and the toe prints are also unique as are palm prints and foot prints. But fingerprints are by far the most simple and effective identification method. Each ridge of the outer skin (epidermis) is doted with sweat pores and anchored to the inner skin (dermis) by a double row of peglike objects called papillae. Injuries which affect the epidermis do not alter the ridge structure and the original pattern returns in the new skin. If the papillae are destroyed however the ridges will disappear. There are five  general pattern shapes or types: the arch, the tented arch, the radial loop, the ulnar loop and the whorl. Whorls are usually circular or spiral arches are shaped like a mound or hill and tented arches have a spike or "steeple" in the centre. Loops have concentric hairpin shaped ridges and are divided into "radial" and "ulnar" to denote their slopes in relation to the radius and ulna bones of the forearm. Ulnar loops slope towards the little finger side of the hand and radial loops slope towards the thumb. The pattern on our fingertips remains the same from birth until death barring deliberate or accidental destruction of the papillae. Fingerprints therefore provide a positive identification and the practice of fingerprinting (dactyloscopy) is an essential part of police procedure.