Triquetrolunate dissociation is the second most common ligamentous cause of carpal (wrist bone) instability. It is an instability between the triquetrum and lunate bones of the wrist. It typically follows a fall onto a wrist positioned in flexion (towards the palm) and inward rotation. This causes stretching or tearing of one of the major interosseous ligaments of the wrist - the lunotriquetral ligament. Triquetrolunate dissociation typically presents as pain on the ulnar (little finger side) or dorsal (back) of the wrist.