Crime Scene Forensics,LLC
Fingerprints
Fingerprints
BASIC FINGERPRINT PATTERNS:
There are three main fingerprint patterns:
1. Loop Patterns:  

In a Loop pattern, the ridges will  flow in one side, recurve, (loop  
around) touch or pass through an imaginary line drawn from the  
delta to the core, and exit the pattern on the same side from which it
entered.

*A loop pattern has only one delta.
*There are two types of loop patterns:
1. Ulnar loop
2. Radial loop

*Loop patterns account for @ 70% of all fingerprints
2. Whorl Patterns:

A whorl pattern consists of a series of almost concentric circles.
* A whorl pattern has two deltas

*There are four types of whorl patterns:
1. Plain whorl,
2. Central Pocket Loop whorl,
3. Double Loop whorl,
4. Accidental whorl

*Whorl patterns account for @ 25% of fingerprints
3. Arch Patterns:

In an arch pattern, ridges flow in one side and flow out the
opposite side. There are no deltas in an arch pattern.

*There are two types of arch patterns:  
1. Plain arch,
2. Tented arch

Arch pattern account for @ 5% of all fingerprints
CLASSIFICATION OF FINGERPRINTS

1. The sorting of fingerprints into file groups so that a file may be set upon on
the basis of fingerprints alone. Fingerprints are classified by general
shape, (arch, loop, or whorl) position within the finger, and relative size.

2. Classification of fingerprints provides for an orderly placing of fingerprint
cards in a file.

Two methods of classifying fingerprints:
1. Henry Classification
2. NCIC Classification
Click here for Glossary of Fingerprint Terms  
Click here for a history of fingerprints
ALL FINGERPRINTS ARE PERMANENT AND INDIVIDUALLY UNIQUE

  • Fingerprints begin forming during the 12th week of gestation, and
    barring surgical or accidental removal of the finger itself, will remain
    permanent for the life of the individual until the body decomposes after
    death.

  • No two fingerprints have ever been found to be alike. No two fingerprints
    on the same hand have ever been found to be alike.  Over 100 years of
    empirical testing and research has supported the uniqueness and
    permanence of friction ridge (fingerprint) arrangements. Modern DNA
    technology can not differentiate between mono zygotic (identical) twins.
    However each of the twenty fingerprints between those twins will be
    unique.

  • Each fingerprint contains minutiae, or ridge characteristics. Fingerprints
    are identified to individuals by examining and comparing the ridge
    characteristics of two different impressions to determine if these
    characteristics occupy the same relative area and position, and if their
    unit relationship to each other matches.
Type lines

-The two innermost ridges which start parallel, diverge,
and                 surround or tend to surround the pattern area.
-When there is a definite break in a type line, the
ridge                         immediately outside of it is considered as its
continuation.
Delta
-The point on a ridge at or in front of and nearest the center of
the    divergence of the type lines.
-The delta area is located as a triangular area where the
ridges        radiate outward in three directions.
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