Ulnar & Radial Loop

a) Ulnar Loop

b) Radial Loop

The loop pattern consists of one or more free recurving ridges and one delta.

In order to distinguish between ulnar and radial loops you must:
1) know from which hand the loop pattern comes from and;
2) place your hand palm side down over top of the impression and determine if the recurving ridges originate from the little finger side or the thumb side.

If the ridges flow in from the little finger side this would be an 'ulnar' loop. If the ridges flow in from the thumb side this would be a 'radial' loop.