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.



For test purposes, fingers of the right hand may be placed on the

corresponding print of the right hand appearing in figure 71, and it

will be noticed that the side of each finger which is nearer to the

thumb on the hand is also nearer to the thumb on the fingerprint card.

Place the fingers of the left hand on the corresponding prints of

the left hand shown in figure 71. It will be noticed that the

arrangement of the prints on the card is the reverse of the

arrangement of the fingers on the hand. The classification of loops

is based on the way the loops flow on the hand (not the card), so that

on the fingerprint card for the left hand, loops flowing toward the

thumb impression are ulnar, and loops flowing toward the little finger

impression are radial.