Scapholunate Interosseous Ligament and Anatomy of SLD:

- Discussion: (see ligaments of the wrist and SLD)
   - three main ligamentous structures which bind the scaphoid to lunate; 
            - volar radioscapholunate ligament (largest); 
            - radiocapitolunate ligament; 
            - scapholunate interosseous ligament (consists of dorsal, proximal, and palmar segments bridging the scaphoid and lunate); 
                      - dorsal portion:
                                - 2-3 mm thick with transversely oriented bundles of collagen;
                                - most important: provides majority of the ligament’s resistance to diastasis between the proximal pole of the scaphoid and lunate;
                      - proximal portion:
                                - SLIL is thin and fibrocartilaginous
                                - blends into the palmar radioscapholunate ligament (Testut)
                      - palmar ligament:
                                - volar to radioscapholunate ligament attachment
                                - ligament is1 mm thick and obliquely oriented 
                 - references:
                       - Radioscapholunate ligament: a gross anatomic and histologic study of fetal and adult wrists. 
                       - The gross and histologic anatomy of the scapholunate interosseous ligament.
                       - The Dorsal Ligaments of the Wrist: Anatomy, Mechanical Properties, and Function 
                       - The radioscapholunate ligament: a gross and histologic description.
          - anatomy of dissociation:
                 - division of the interosseous scapholunate ligament + sectioning of the radioscaphocapitate ligament + clenched fist positioning will
                        cause an 8 mm gap vs avg of 2 mm gap (w/ ligament intact);
                 - to have true scapholunate dissociation, 2 out of 3 ligaments must be significantly injured (secondary constraints being palmar radiocapitate and distal STT);
          - reference: 
                 - The effect of scapholunate ligament section on scapholunate motion. 
                 - The role of the dorsal intercarpal ligament in dynamic and static scapholunate instability. 
                 - Dorsal Wrist Ligament Insertions Stabilize the Scapholunate Interval: Cadaver Study. 
                 - Biomechanical evaluation of ligamentous stabilizers of the scaphoid and lunate 
                 - Biomechanical evaluation of the ligamentous stabilizers of the scaphoid and lunate: Part II.
                 - Biomechanical Evaluation of the Ligamentous Stabilizers of the Scaphoid and Lunate: Part III. 
                 - The effect of scapholunate ligament section on scapholunate motion.