Fingerprint patterns

There are three main fingerprint patterns;loops, whorls and arches.

Arches are found in around 5% of fingerprints.The lines run fron one side to the other of the pattern, making no backward turn.There are four types of arch patterns: plain arches, radial arches, ulnar arches and tented arches.Plain arches have an even flow of ridges from one side to the other of the pattern. The ridges of radial arches slope towards the thumb, have one delta and no re-curving ridges. On ulnar arches, the ridges slope towards the little finger, have one delta and no re-curving ridges. Tented arches have an angle, an up thrust, or two of the three basic characteristics of the loop.

Loops occur in about 60-70 % of fingerprint patterns encountered. One or more of the ridges enters on either side of the impression. The flow of the pattern in radial loops runs in the direction of the radius (toward the thumb). Ulnar loops are named after the ulna, a bone in the forearm. The ulna is on the same side as the little finger and the flow of the pattern in a ulnar loop runs in the direction of the ulna (toward the little finger).

Whorls are seen in about 25-35 % of fingerprint patterns encountered. In a whorl, some of the ridges make a turn through at least one circuit.There are four types of whorl patterns. Plain whorls consist of one or more ridges which make or tend to make a complete circuit with two deltas, between which an imaginary line is drawn and at least one re-curving ridge within the inner pattern area is cut or touched. Central pocket loop whorls consist of at least one re-curving ridge. Central pocket loop whorl ridges make one complete circuit which may be spiral, oval, circular or any variant of a circle. Double loop whorls consist of two separate and distinct loop formations with two separate and distinct shoulders for each core. Accidental whorls consist of two different types of patterns with the exception of the plain arch.