SO - Crime Busters - Fingerprints

15 terms by jtmbox Teacher

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Arches

Basic type 1. Includes tented arch and plain arch.
The Arch pattern is made up of ridges lying one above the other in a general arching formation.

Tented arch

In-depth arch name. No delta. An arch with a sharp corner at the top point, resembles a triangle.

Plain arch

In-depth arch name. No delta. An gentle slope up with a more rounded top point, like a small hill.

Loops

Basic type 2. Loops up to one side like a beanish shape and has one delta. Includes Ulnar loop and Radical Loop.

In order to distinguish between ulnar and radial loops you must:
1) know from which hand the loop pattern comes from and;
2) place your hand palm side down over top of the impression and determine if the recurving ridges originate from the little finger side or the thumb side.

If the ridges flow in from the little finger side this would be an 'ulnar' loop. If the ridges flow in from the thumb side this would be a 'radial' loop.

Ulnar Loop

In-depth loop name. A loop pointing towards the pinky

Radial Loop

In-depth loop name. A loop pointing towards the thumb

Whorls

Basic type 3. Has two deltas and looks like a target. There are many sub-categories of whorls, such as (but not limited to)-

Plain whorls

In-dept whorl name. Most important to know; sometimes simply referred to as "whorl"

Double loops

In-depth whorl name.
In the twinned loop pattern, the recurving ridges present two loop formations, separate and apart. There are two points of delta. The flows for the deltas originate from the same side of the pattern.

Central Pocket Whorl

The central pocket loop pattern consists of one or more free recurving ridges and two points of delta. When the line of the fingerprint disc is placed on the two points of delta, it will fail to bisect any of the ridges belonging to the core group.

Lateral pocket loop

In the lateral pocket loop pattern, the recurving ridges present two loop formations, separate and apart. There are two points of delta. The flows for the deltas originate from the same side of the pattern.

Accidental whorls

The accidental pattern will contain two points of delta. One delta will be related to a recurve and the other will be related to an upthrust. Rarely tested.

Tracings

rare tested whorl name. It is highly unlikely that they will ask for one of these, so this should be the last thing you should worry about learning. However, the most important whorls to know are the plain whorl and double loop.

Composite

The composite pattern is composed of two or more different patterns, separate and apart exclusive of the arch.

Strategy

1. Practice identifying and comparing fingerprints.
2. There are 3 basic categories of fingerprints(arches, loops,and whorls). They are easily identified by there general shape and number of deltas (triangles made from ridges).
3. Make sure you know if your event supervisor is looking for the basic type (loop, arch, whorl), or the more in-depth name (Tented Arch, Ulnar Loop, etc.).

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