In 1896, an English police official, Sir Edward Richard Henry, invented the fingerprint classification system used today. Fingerprints fall into three main categories: the arch, the loop and the whorl. Within these three categories, there are six subtypes. In addition, there are two composite type fingerprints that combine characteristics from the other subtypes.
This fingerprint is characterized by a slightly rising ridge pattern that flows from one side of the finger to the other. According to The Science Spot, the arch family of fingerprint types comprises less than 5 percent of all fingerprints and is therefore the least common.
Like a plain arch, the ridges flow from one side of the finger to the other. However, in the middle the ridges rise sharply, forming a tent-like structure.
A loop is formed when fingerprint ridges turn backward but do not twist completely around. Loops are classified by the direction they turn when looking at the fingerprint on the hand, not a fingerprinting card. An ulnar loop turns toward the little finger.
Like an ulnar loop, this type of fingerprint is defined by its appearance on the hand. A radial loop turns toward the thumb.
A plain whorl fingerprint appears to create an unbroken circular patter reminiscent of a spiral or swirl. This is the most common type of fingerprint.
Central Pocket Whorl
In this type, one or more of the central ridges recurves to form a smaller inner whorl.
Double Loop Whorl
This type of fingerprint also might be a twinned loop or lateral pocket loop. According to the Federal Bureau of Investigation, although there are subtle differences between these three types, the bureau chose to classify all under Double Loop Whorl rather than attempt to distinguish them. Double loop whorl and twinned loop both appear to be two distinct loops that curve back on one another in opposing directions, similar to the yin-yang pattern. A lateral pocket loop makes a sharp turn back, forming a central pocket.
Central Pocket Loop
Classified as a composite fingerprint, the loop recurves within itself to form a pocket.
A composite fingerprint described as either a loop or a whorl, accidental type fingerprints possess two or more characteristics of the tented arch, whorl or loop families combined. The plain arch is not included because it does not have any distinctive characteristics.