LIGAMENTS OF WRIST
The ligaments of the wrist are divided into three separate groups: the dorsal intercapsular, the volar radiocarpal, and the interrosseous ligaments. Confusion regarding these structures often centers on the numerous different names utilized to identify these structures.
The volar radiocarpal ligaments are the most critical of these structures and provide the majority of ligamentous stability to the carpus. The volar ligaments consist of the radioscaphocapitate ligament, the long/short radiolunate ligaments, the radioscapholunate ligaments (more of a vascular conduit), and the ulnotriquetral and ulnolunate ligaments. The radioscaphocapitate ligament is a critical restraint to ulnar translocation of the carpus and must be preserved during proximal row carpectomy and/or during radial styloidectomy. The space of Poirier is a weak point between the radioscaphocapitate and long radiolunate ligaments, where the lunate can dislocate during a lunate dislocation. During a volar approach to lunate/perilunate dislocations this space can be sutured to provide increased stability to the injured carpus. The dorsal intercapsular ligaments consist of the dorsal radiocarpal and dorsal intercarpal ligaments. These provide additional structural support to the carpus, and numerous “ligament-sparing approaches” to the wrist have been described to preserve these structures. These dorsal ligaments can also be utilized to correct carpal instability by being transferred to function as a capsulodesis. There are numerous intercarpal ligaments, the most critical being the scapholunate and lunotriquetral ligaments. Disruption of these intercarpal ligaments can lead to dorsiflexed or volar-flexed intercalated segment instability (DISI or VISI) deformities, respectively. Repair of these ligaments can be performed in the acute setting, whereas numerous reconstructive procedures have been described for use in the chronic setting when symptomatic.
The triangular fibrocartilage complex (TFCC) describes a confluence of soft tissue structures that stabilize the distal radioulnar joint (DRUJ) and transmit forces across the ulnocarpal joint. The individual components include dorsal and palmar radioulnar ligaments, meniscus homologue, ulnotriquetral and ulnolunate ligaments, articular disc, and the extensor carpi ulnaris subsheath. The dorsal and palmar radioulnar ligaments are most critical for DRUJ stability. TFCC pathology can often be diagnosed and treated with arthroscopic techniques.