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Natatory Ligament


- Anatomy:
    - other name for the superficial transverse metacarpal ligament;
    - these ligamentous fibers extend between the web spaces of the digits, and lie immediately beneath the skin, and helps create web space;
    - digital nerves & vessels pass deep or dorsal to natatory ligaments;
          - because the spiral band passes deep to the N/V bundle (just before it forms coalescence w/ the natatory ligament) the 
                aneurovascular bundle will be drawn to the midline if either the natory ligament or the spiral band become contracted;
    - this ligament passes in radial-ulnar direction at each web space, w/ some fibers going distally to PIP on either side of each finger;
    - the natatory liagment normal tightens as the finger abduct;
          - in Dupuytren's contracture, there is thickening and contracture of the natatory ligament, which leads to loss of abduction;
          - because the natatory liagment coalesces w/ the lateral cords, contracture of the natatory ligament may lead to PIP Joint contracture;
    - deep transverse ligament:
          - lies 3-4 mm deep to superficial transverse ligament;
          - connects the MP volar plates together;
          - digital vessels run between superficial and deep ligaments;
          - lumbrical muscles passes palmar to deep transverse ligament;
          - dorsal interossei pass dorsal to deep transverse ligaments;

- Pathology:
    - natatory ligament is commonly involved in Dupuytren's contracture;
    - contracture of ligament prevents separation of fingers & contributes to contracture at the PIP Joint and web space contracture;
    - ligament also exists in web space of thumb & terminates at proximal crease of the thumb;
         - can limit abduction & extension of thumb