Forensic Workshop T. Trimpe 2006 http://sciencespot.net Fingerprint Principles

Forensic Workshop T. Trimpe 2006 http://sciencespot.net Fingerprint Principles According to criminal investigators, fingerprints follow 3 fundamental principles: A fingerprint is an individual characteristic; A fingerprint pattern will remain unchanged for the life of an individual Fingerprints have general characteristic and ridge patterns Fingerprint Classes There are 3 specific classes for all fingerprints based

upon their visual pattern: arches, loops, and whorls. Each group is divided into smaller groups as seen in the lists below. Arch Plain arch Tented arch Loop Radial Loop Ulnar loop Whorl Plain whorl Central pocket whorl

Double loop whorl Accidentical Arches Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present. Spike or tent Plain Arch Ridges enter on one side and exit on the other side. Tented Arches

Similar to the plain arch, but has a spike in the center. Loops Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones. Delta Ulnar Loop (Right Thumb) Loop opens toward right or the ulna bone.

Radial Loop (Right Thumb) Loop opens toward the left or the radial bone. NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop. Whorls Whorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental.

Plain Whorl Central Pocket Whorl Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. If none of the center core touches the line, it is a central pocket whorl. Whorls Part 2 Double Loop Whorl

Accidental Whorl Delta Delta Double loop whorls are made up of any two loops combined into one print. Accidental whorls contain two or more patterns

(not including the plain arch), or does not clearly fall under any of the other categories. Identify each fingerprint pattern. Plain Whorl Double Loop Radial Loop Right Hand

Left Hand Tented Arch Plain Arch Right Hand Right Hand Left Hand Interesting Info Fingerprint Factoid: 60% of people have loops, 35% have whorls, and 5% have arches

Did you know? Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting dactylograms, otherwise known as fingerprints.