Fig. (5) When load is applied to the hand (F) with a specific
moment ( L), the fixed fulcrum (E) is the DRUJ. Stability is defined
as equality in forces, with their specific moments, working on a
fixed fulcrum. If the elbow is stable, the load between elbow and
DRUJ (F’ x L’) will equal the load between the DRUJ and the hand
(F x L) in a stable situation.