(1) If you cut your finger, does the scar change your fingerprint
permanently? Can the original fingerprint be matched reliably?
A Scar on the finger interferes with print ridges, but creates a new
unique print. Since matching a fingerprint doesn't require the whole
print to be intack, then yes, the original fingerprint can be matched.
In fact the most famous case regarding this issue is John Dillinger
who had his finger tips treated with acid to remove his prints. The
ridge patterns grew back in his case.
(2) If you slice off the skin from a fingertip, does the skin (when it grows
back) have a fingerprint? Is it the same fingerprint?
If you only remove the top few layers, yes, they will grow back and
have the same fingerprint, as Dillinger found out. If you remove the
whole tip, all the skin, then scar tissue will grow back, and will be
easily identifiable, and of course, there is the whole rest of the
hand to gain prints from. Modern CSI doesn't simply go for finger tip
prints. Hands, fingers, palms, the works are used for identification.
A great page on the skin, and its layers can be found on Ridges and
Furrows, where this quote comes from ...
" Once this blueprint has been established, in the stratum basale
(generating layer) of the epidermis on the fetus prior to birth, it
does not change except for injury, disease or decomposition after
death. Injury to the generating layer (Stratum basale) may affect
the skin's ability to regenerate and scar tissue forms."
(3) If you graft skin from another part of your body onto your fingertip, do you
have normal sensation but a different fingerprint?
The most famous case showing this attempt is Robert Phillips, another
gangster, who had the skin on his fingertips removed by plastic
surgery and replaced with skin grafts taken from his chest. He was
identified by the second sections of his fingers.
As for the prints, Howard L. Updegraff, M.D. in the 1934 issue of The
American Journal of Surgery, vol. XXVI, pp 533--534, stated that
graphs from other parts of the body would not reproduce fingerprints.
"Ordinary skin taken from other parts of the body, with the exception
of the palms of the hands and the soles of the feet, does not contain
the characteristic ridges and will not develop them on
Scar tissue of any type is not as sensitive as the unscarred skin. In
most cases however, with skin grafting, and today's technology, the
loss sensation would probably be unnoticeable.
(4) How reliable is a match? Obviously, DNA is better, but how good
(or bad) is a fingerprint match on a modern computer database?
Actually fingerprints are more useful for unique identification than
DNA, since twins, triplets and other multiple births sometimes share
DNA matches, but the fingerprints are always unique between them.
The reliability of the matching could be described as "very good"
though mistakes have been made, and some of the more famous cases of
these are within the links I have for you below. It is very rare today
that identification is the only identification being looked at for any
There is a good site called Problem Idents, which discusses the
problems of identification through finger printing.
References and Resources
Skin grafts taken from one person and transplanted to another or taken
from animals and transferred to humans are so seldom successful that
they may be eliminated from consideration. Where the very rare case
has been successful at first, ultimately the graft was replaced by
scar tissue. Ordinary skin taken from other parts of the body, with
the exception of the palms of the hands and the soles of the feet,
does not contain the characteristic ridges and will not develop them
Fingerprint experts would state that scars and flexion creases are
never used in the identification process. However most experts would
agree that they are used in the searching and the initial stages of
the identification process. All these are aspects of the
identification process. All experts use the number of characteristics
and the coincident sequence to explain and demonstrate an
Michele Triplett's Fingerprint Terms
NIST Image Group's Fingerprint Research
Fingerprint Identification - AFIS
Do fingerprints of family members have anything in common?
Changing of Fingerprints
Raes and other detectives say thieves frequently use a little Super
Glue, even hair spray, to alter their
Forensic Fact Files Fingerprints
The American gangster John Dillinger had his fingertips treated with
acid in the 1930s to remove the ridge patterns, and Robert Phillips,
another American criminal, had the skin on the fingertips removed by
plastic surgery and replaced with skin grafts taken from his chest.
Both attempts failed miserably. Dillinger's ridge patterns reappeared,
and Phillips was identified by impressions taken from the undoctored
second phalanges of his fingers.
Putting a finger on it ? the loops and whorls of
fingerprint +alter +surgery
fingerprint +alter +plastic surgery
finger print alteration
fingerprint +"scar tissue"