A. Three basic patterns—loops, whorls, and
arches
Whorl
Loop
Arch
1. Loop
a. = one or more ridges entering from one
side, curving, then going out from same
side entered
b. contains a delta and a core
c. ~ 65% of all fingerprints have loops
d. Subcategories of loop
i. Radial loop = opens toward the thumb, which
is toward the radius
ii. Ulnar loop = opens toward the little finger,
which is toward the ulna
(NOTE: need to know which hand print came
from to determine radial or ulnar loop . . . ulnar
loops are more common)
Ridges flow in the
direction of the thumb
Radial Loop
Right Hand
Ridges flow in the direction
of the little finger
Ulnar Loop
Left Hand
Fingerprint Techniques Manual, page 13
--New Mexico Department of Health
--http://dhi.health.state.nm.us/elibrary/cchspmanual/fingerprint_manual.pdf
2. Whorls
a. = contains at least two deltas and a core
b. ~ 20% of fingerprints are plain whorls, ~ 10%
are composite or accidental whorls
c. Subcategories of whorl
i. plain whorl
ii. central pocket loop whorl
iii. double loop whorl
iv. accidental whorl
Whorls have at least one ridge that makes (or tends to make) a
complete circuit. They also have at least two deltas. If a print has
more than two deltas, it is most likely an accidental.
Plain
Whorl
Central
Pocket
Whorl
Draw a line between the two deltas in the plain and central pocket
whorls. If some of the curved ridges touch the line, it is a plain
whorl. If none of the center core touches the line, it is a central
pocket whorl.
This slide: http://sciencespot.net/Pages/classforsci.html#fiingerprint
3. Arches
a. = all ridges enter on one side and exit on
the other
b. contain NO delta or core
c. least common
d. Subcategories of arch
i. plain arch
ii. tented arch
Fingerprint Techniques Manual, page 9
--New Mexico Department of Health
--http://dhi.health.state.nm.us/elibrary/cchspmanual/fingerprint_manual.pdf
Fingerprint Techniques Manual, page 8
--New Mexico Department of Health
--http://dhi.health.state.nm.us/elibrary/
cchspmanual/fingerprint_manual.pdf
B. Ridge classification (Individualization)
1. Minutiae = fine structure of ridge
characteristics include . . .
ridge ending
bifurcation
dot
short ridge
island (enclosure)
core
delta
http://shs.westport.k12.ct.us/forensics/04-fingerprints/handout.htm
The computer database uses minutiae to
compare fingerprints and determine a
match.
Circle using the Promethean pen

http://ridgesandfurrows.homestead.com/pict
ures.html

http://dhi.health.state.nm.us/elibrary/cchspmanual/finger
print_manual.pdf



If a fingerprint has no deltas, it is an arch.
If a fingerprint has one delta, it is a loop.
If a fingerprint has two or more deltas, it is a whorl.
It’s time to take
some prints!
This slide: http://sciencespot.net/Pages/classforsci.html#fiingerprint