Fingerprints

Plain Arch

Ridges enter on one side of the impression and flow or tend to flow out the other with a rise or wave in the center.

Tented Arch

Most of the ridges enter upon one side of the impression and flow or tend to flow out upon the other side, however the ridges at the center do not. Tend to form an upthrust or angle at the center of the pattern.

Loop

A type of fingerprint pattern in which one or more of the ridges enter on either side of the impression, recurve, touch or pass an imaginary line drawn from the delta to the core, and terminate or tend to terminate on or toward the same side of the impression from whence such ridge or ridges entered.

Radial Loop

Loops that enter and exit (open up) on the side of the radius bone (thumb).

Ulnar Loop

Loops that enter and exit (open up) on the side of the ulna bone (pinky).

Whorl

The type of pattern in which at least two deltas are present with a recurve in front of each.

Plain Whorl

Has two deltas and at least one ridge making a complete circuit, which may be spiral, oval, circular or any variant of a circle. An imaginary line drawn between the two deltas must touch a recurving ridge in the pattern area.

Central Pocket Loop

Has two deltas and at least one ridge which makes a complete circuit. A line drawn between the two deltas must not touch or cross any recurving ridges within the inner pattern area.

Double Loop

Two separate loop formations, with two separate and distinct sets of shoulders and two deltas.

Accidental

Combination of two different types of patterns, with the exception of the plain arch, with two or more deltas; or a pattern which possesses some of the requirements for two or more different types or a pattern which conforms to none of the pattern definitions.