Measurement of the carpal bone angles helps to indentify carpal instability. The normal angle is depicted in the left image of each group. The drawing on the right depicts abnormal angles when there is a dorsal intercalation scaphoid pattern of carpal instability. A scapholunate angle of >80° indicates scapholunate dissociation or volarly displaced scaphoid fracture. The capitolunate angle is usually less than 15°. The radiolunate angle is normally <15°.
