They are divided into plain whorls, central pocket whorls, double loops, and accidental whorls.Ī plain whorl, figure 16-6, view A, has two deltas and at least one ridge making a complete circuit, which may be spiral, oval, or any variant of the circle. Whorls are those types of patterns in which the ridges form concentric circles or spirals or some variant of this geometric form. Radial loops, figure 16-5, view D, are those types of patterns in which the loops flow toward the thumbs. Ulnar loops, figure 16-5, view C, are those types of patterns in which the loops flow in the direction of the little fingers. The classifier divides loops into two types-ulnar and radial. The loop must have three essential characteristics-a sufficient recurve, and its continuance on the delta side until the imaginary line is reached a delta and a ridge count of at least one. Tented arches, figure 16-5, view B, are similar to plain arches with the exception that the ridges in the center form a definite angle or one or more ridges at the center form an upthrust or they approach the loop type, possessing two of the basic characteristics of the loop but lacking in the third.Ī loop has 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 which the ridge or ridges entered. In plain arches, figure 16-5, view A, the ridges enter on one side of the impression and flow or tend to flow out the other side with a rise or wave in the center. Plain, Tented Ulnar, Radial Plain, Central Pocket, Double Loop, Accidental They are further classified into eight different types as follows: Points of distinction to be made in determining exactly what constitutes a particular pattern a trained classifier will use in classifying the print.įingerprint patterns have three basic classification designations. The basic characteristics in a fingerprint pattern are type lines, deltas, and the core. Fingerprints and major case prints taken for comparison with latent prints should always be as clear and complete as possible. Every investigator should be familiar with the basic fingerprint pattern types to improve the quality of inked impressions taken for submission to identification bureaus.