In radiology, the Terry-Thomas sign is a scapholunate ligament dissociation on an anteroposterior view of the wrist.

[1][2] Most commonly a result of a fall on the outstretched hand (FOOSH), the scapholunate ligament ruptures resulting in separation of the lunate and scaphoid bones.

This burst causes the scaphoid bone to dorsally rotate.

[4] The resulting separation between the scaphoid and lunate bones leaves a space on the x-ray that is similar to the gap comedian Terry-Thomas had between his front teeth.

For newer radiology students who do not know who Terry-Thomas was, this finding might also be known as the David Letterman sign.