Ballottement test (shuck test): Lunotriquetral instability

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- Discussion:
    - triquetrum is displaced dorsally and palmarly on the lunate,
          demonstrating increase excursion over the normal side and often a
          painful crepitus;
    - compression test: displacement of the triquetrum ulnarly during
          radioulnar deviation, which is also painful;
Shear test:
      - for triquetrolunate strain;
      - shear force applied at this joint while stabilizing lunate dorsally and
            pisotriquetral plane volarly;