Bicompartmentalization of the radiocarpal joint

Seven wrists are presented with a septum connecting the lunotriquetral interosseous ligament and triangular fibrocartilage, resulting in bicompartmentalization of the radiocarpal joint. In all of the 7 wrists, having no history of trauma, the septums were suspected to be of congenital origin. The histopathology of the septum in 1 cadaver wrist showed a fibrocartilaginous structure. Two types of radiocarpal joint bicompartmentalization were identified by arthrography. Type 1 (2 wrists) had a septum with normal (intact) lunotriquetral interosseous ligament, and type 2 (5 wrists) had a septum with a communicating defect of the lunotriquetral interosseous ligament. The septum is most likely a congenital malformation caused by a disturbance of the vacuolization of the mesenchymal mass between the forearm and carpus.