SO - Crime Busters - Fingerprints

science olympiad 2013
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Tented arch
No delta. An arch with a sharp corner at the top point, resembles a triangle.
Plain arch
No delta. An gentle slope up with a more rounded top point, like a small hill.
Ulnar Loop
A loop pointing towards the pinky
Radial Loop
A loop pointing towards the thumb.
Double loops
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.
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.
Plain whorls
Most important to know: sometimes simply referred to as "whorl".
Central Pocket Whorl
The central pocket whorl pattern consists of one or more free recurving ridges and two points of delta.
Accidental whorls
The accidental pattern will contain two points of delta. Rarely tested.
Composite
The composite pattern is composed of two or more different patterns, separate and apart exclusive of the arch.
Deltas
Triangles made from ridges.
Arch pattern
The Arch pattern is made up of ridges lying one above the other in a general arching formation.
Loop pattern
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.
Whorl pattern
Whorls have two deltas and look like a target.
Island
An Island is a line-type which stands alone.
Bifurcation
Bifurcations are splitting lines in the pattern.
Core
Is the approximate center of the finger pattern impression
Ellipse
An Ellipse is a circular or oval shaped line-type which is generally found in the center of Whorl patterns.