Integumentary Notes – Fingerprints

Fingerprints – “______”

-caused by the presence of tiny ______in the outer skin

  • they develop before birth(usually between 2-3 months in womb)
  • see animations of their creation at:
  • contain rows of pores that connect to ______glands
  • Latent (______) fingerprints are created when sweat and oils are transferred to a surface
  • increase ability to ______and reduce slippage
  • there are hills (______) and valleys (______)

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

  • each fingerprint has at about ______individual ridge characteristics
  • even identical twins have different fingerprints (though they are very similar)
  • two identical prints have never been found
  • calculated that probability of finding identical prints is 1 in ______

-fingerprints can be altered

  • must cut more 1-2 ______beneath skin’s surface to permanently damage
  • must damage the ______

  • otherwise, ridge patterns will reappear as before
  • 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

  • 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
  • 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)
  • 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 ______)

  • identity, number, and relative location of characteristics create individuality
  • examples:
  • 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.