The Henry Classification System

There are two (2) elements required for a pattern to be considered a
whorl. The pattern must be some
variant form of a circle (circular, spiral, or oval shaped). 
Whorls have more pattern types than arches or loops. 
A whorl can be classified as plain, central pocket loop, “S” type,
interlocking, double loop, or accidental. 

 A plain whorl
consists of at least one ridge or more making a complete circuit. 
Plain whorls have two (2) deltas. 
If a line (real or imaginary) is drawn between the two (2) deltas, then
the line must touch one or more ridge in the pattern

 A central pocket loop whorl has one or more recurving ridge(s). It also has two
(2)  deltas.  When a line is drawn (real or imaginary), a recurving ridge is not touched in the inner pattern.

A double loop whorl has two loop formations that are separated
and has two (2) deltas.  Since
these whorls have two loops, a ridge count is not needed.

“S”type  whorls
appear to have an “s”formation in the center of the pattern. 
They may look very similar to double loop whorls, but the ridge flows the
same direction.  An accidental
whorl is a result of two (2) pattern types with the exemption of plain
arches.  An accidental whorl has
two (2) or more deltas present. 
Accidental whorls do not conform to any rules of the whorl patterns.

When classifiying whorls, use a W to indicate all whorl
types.  The type of whorl will be
indicated in the upper right corner of the block. 
A plain whorl is represented by a capital P. 
A central pocket whorl is represented by a capital C. 
A double loop whorl is represented by a capital D. 
Lastly, an accidental whorl is represented by a capital X. 
A backslash will be drawn under the classification (P, D, C, D, or
X).   Beneath the
classification and under the backslash, write the whorl tracing. The tracing
tells examiner if the whorl is inner, meets, or outer of the right
delta. Images below the chart are from Forensic Press .


The FBI processes about 7000 new fingerprints every day.   60-65% of people have loop
patterns.  30-35% have whorls and
only 5% have arches.