"The signet ring sign, cortical ring sign, or just the ring sign refers to the rounded cortex of the scaphoid tubercle on an AP or PA wrist radiograph due to rotatory subluxation from flexion of the scaphoid. It is seen in injuries of the scapholunate ligament (scapholunate dissociation) and the related perilunate and lunate dislocations, but can be seen in normal wrist radiographs 1,2."
"The signet ring sign, cortical ring sign, or just the ring sign refers to the rounded cortex of the scaphoid tubercle on an AP or PA wrist radiograph due to rotatory subluxation from flexion of the scaphoid. It is seen in injuries of the scapholunate ligament (scapholunate dissociation) and the related perilunate and lunate dislocations, but can be seen in normal wrist radiographs 1,2."