Solution: Scapholunate dissociation is the most common carpal instability and can lead to a typical pattern of wrist arthritis, which has been termed scapholunate advanced collapse SLAC wrist. On the AP View you will see the "Terry Thomas" sign, which is an increase in the gap between scaphoid and lunate (normal 1-2 mm) as in this case. Progressive flexion and foreshortening of the scaphoid leads to the scaphoid ring sign, seeing scaphoid end on, also seen on this case. This is an important diagnosis to make because the preferred treatment is surgical repair of the injured ligaments within 3 weeks.