Fingerprint pattern classifications

Fingerprints are given three main classifications based on the general characteristics of their pattern, those being loops, whorls and arches.

The loop pattern is the most commonly occurring. In a loop pattern, one or more ridges enters on one side of the print, loops around, and exits on the same side it entered. There are two main types of loop patterns; the radial loop and the ulnar loop. The ulnar loop is the most common, and is characterized by the loop opening towards the little finger, opposite from the thumb. It is named after the ulna, the bone in the forearm that connects to the hand on the side of the little finger. The radial loop is identical to the ulnar loop with the exception that it opens towards the thumb; it is named after the radius, which is the bone in the forearm that connect to the thumb.

An Ulnar loop print pattern.

Whorls are less common then loops. Any pattern in which one or more ridges makes a complete circuit or circle is a whorl.

A plain whorl print pattern.

The least common variety of fingerprint pattern is the arch. An arch pattern is characterized by having each ridge enter one one side of the pattern, and exit on the opposite side so as that no ridge loops or turns back on itself. Often the ridges will turn upwards in theappearance of anarch, hence the name of the pattern.

An arch print pattern.