Wisconsin Department of Justice Identification Manual - Imprimus ...

Tented Arch
Loops
A LOOP is that type of pattern in which one or more ridges enter upon either side,
recurve, touch or pass an imaginary line between delta and core and pass out or tend
to pass out upon the same side the ridges entered.
RADIAL and ULNAR LOOPS
The terms "radial" and "ulnar" are derived from the radius and ulna bones of the
forearm. Loops which flow in the direction of the ulna bone (toward the little finger)
are called ulnar loops and those which flow in the direction of the radius bone are
called radial loops. The classification of loops is based on the way the loops flow on
the hand (not the card), so that on a fingerprint card for the left hand, loops flowing
toward the thumb impression are ulnar, and loops flowing toward the little finger
are radial.
Loop (Ulnar on left hand, Radial on right hand)
Loop (Radial on left hand, Ulnar on right hand)
Wisconsin Department of Justice Identification Manual Fingerprint Patterns • 85