What sign does this X-ray demonstrate?
Scapho-lunate dissociation (Terry Thomas Sign)
- Terry Thomas was a famous Welsh actor who sported a gap between his two front teeth of 6mm. The Terry Thomas sign is present in the carpus of patients with scapholunate dissociation (SLD) and it specifically refers to the width of the scapholunate junction on a true AP view of the carpus. When positive the gap is greater than 3mm.
- A scapholunate diastasis of 3mm is a normal variant and, as routine films do not always show the scapholunate junction accurately, comparison should be made with the other hand. A clenched fist view of the carpus with the hand in ulnar deviation can also be performed