Integumentary Notes – Fingerprints

Fingerprints – “______”

-  caused by the presence of tiny ______in the outer skin

o  they develop before birth (usually between 2-3 months in womb)

§  see animations of their creation at: http://www.clpex.com/images/Animations/Fusion.htm http://www.clpex.com/images/Animations/Minutia.htm

o  contain rows of pores that connect to ______glands

§  Latent (______) fingerprints are created when sweat and oils are transferred to a surface

o  increase ability to ______and reduce slippage

o  there are hills (______) and valleys (______)

-  the arrangement and number of these ridges are unique to every individual

o  each fingerprint has at about ______individual ridge characteristics

o  even identical twins have different fingerprints (though they are very similar)

o  two identical prints have never been found

o  calculated that probability of finding identical prints is 1 in ______

-  fingerprints can be altered

o  must cut more 1-2 ______beneath skin’s surface to permanently damage

§  must damage the ______

§  otherwise, ridge patterns will reappear as before

o  removed by ______

§  however, new scar tissue will become the new identifier

§  Example – John Dillinger (______gangster)

·  Tried to use acid to remove ridge patterns, but his wounds healed, and comparisons between previous fingerprints and new fingerprints showed at least _____ individual identifiers

-  one family in America has a genetic mutation where they do not have fingerprints

However, they do have a few characteristic ridges, which can help identify them

Images of Fingerprint patterns

Three Main Categories:

______– plain and tented

______– ulnar and radial

______– central pocket loop, plain whorl, double loop, accidental

Accidental Whorl

Fingerprint ridge patterns

-  Best way to determine is by looking at “deltas” and “cores”

-  ______– triangular pattern (blue, lower-right box)

-  ______– end of ridge, with other ridges wrapped around it (red, upper-left box)

Three main categories

o  Arch – 5% of fingerprints

§  Ridgelines start from one side of the fingertip, rise at the center, and exit on the other side of the fingertip

·  Usually ___ true deltas

PLAIN ARCH
TENTED ARCH

§  ______– rounded at the top

§  ______– pointed at the top

o  Loop – 60-65% of fingerprints

§  Ridgelines start and end on the same side of the fingertip

·  Has _____ delta

§  Radial – opens toward the thumb (and the ______bone)

- ______

§  Ulnar – opens toward the little finger (and the ______bone)

o  Whorl – 30-35% of fingerprints

§  Ridgelines are circles that do not begin or end on either side of the fingertip

·  Has ______deltas

§  Plain – at least one ridge makes a complete circle

·  Line formed between the two deltas ______intersect ridge forming a complete circle

Plain whorl / Two deltas marked / Line joining deltas

§  Central pocket – complete circle is offset – usually much higher or left/right than a plain whorl

·  Line formed between the two deltas ______intersect ridge forming a complete circle

Line joining two deltas -
Central Pocket Whorl / Line joining two deltas – Central Pocket Whorl / Line joining two deltas – Plain Whorl

§  Double loop – contains ______separate and distinct loops

Double Loop / Arrows pointed to each core / Each loop indicated

§  ______– has multiple twists and turns

·  Has more than two ______

Ridge Characteristics (also known as ______)

o  identity, number, and relative location of characteristics create individuality

o  examples:

o  most fingerprints have about _____ individual ridge characteristics

§  however, most fingerprints found at a crime scene are partial fingerprints

Minutiae are the discontinuities of the ridges:

· ______- the points at which a ridge stops

· ______- the point at which one ridge divides into two

· ______- ridges slightly longer than dots, occupying a middle space between two temporarily divergent ridges

· ______- two ridges which cross each other

· ______- the inner point, normally in the middle of the print, around which swirls, loops, or arches center. It is frequently characterized by a ridge ending and several curved ridges.

· ______- the points, normally at the lower left and right hand of the fingerprint, around which a triangular series of ridges center.