[4][5] A dynamic scapholunate instability is where the scapholunate ligament is completely ruptured, but secondary scaphoid stabilizers are still preserved;[6] these are the scaphotrapezial (ST), scaphocapitate (SC) and radioscaphocapitate (RSC) ligaments.

[8] The fist X-ray is often made if there is no convincing Terry Thomas sign.

A fist X-ray of a scapholunate ligament rupture will show a descending capitate bone.

Making a fist will give pressure at the capitate, which will descend if there is a rupture in the scapholunate ligament.

Treatment will vary depending upon the degree of injury and can range from observation and direct ligament repair through to reconstruction.