Exam for Scapholunate Instability

- See:
      - Carpal Instability:
              - scapholunate advanced collapse
              - scapholunate instability  

- Discussion:
    - scapholunate and lunate injuries cause tenderness just distal to Lister's tubercle;
           - marked prominence of the entire carpus dorsally may indicate of a perilunate dislocation;
    - SLD is characterized by limited range of motion and increased weakness;
    - Watson test:
           - this test provokes dorsal subluxation of the proximal scaphoid over the dorsal rim of the radius, as the wrist is radially deviated;
           - is performed by grasping the patient's hand from its ulnar aspect of the small metacarpal with the examiner's thumb on the palmar surface of the distal pole of the scaphoid;
                - alternatively, the patient's hand is grasped by the examiner's hand from the radial aspect of the index metacarpal with the thumb and the palmar surface;
                - it is critical for the examiner's thumb to apply pressure to the distal pole of the scaphoid, in order to prevent it from flexing;
           - move wrist from ulnar to radial deviation w/ distal tuberosity compressed;
           - as scaphoid flexes to more vertical orientation w/ radial deviation, tuberosity compression forces proximal pole subluxation dorsal to lip of radius;
           - as the examiner's thumb pressure is removed, the subluxed scaphoid reduces, and may produce a palpable clunk and dorsal wrist pain (indicating instability of the scapholunate ligament);
           - this test has been criticized for low specificity;
                 - in the study by Wolfe, et al (1997), 36% of normal individuals had a positive shift test;
                        - when examined flouroscopically, many of these individuals had a capitolunate instability;
                        - Kinematics of the scaphoid shift test.

The scaphoid shift test.

Examination of the scaphoid

Radiographic observation of the scaphoid shift test.


Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, November 27, 2012 1:19 pm