BICOMPARTMENTALIZATION OF THE RADIOCARPAL JOINT

Seven wrists are presented with a septum connecting the lunotriquetral interosseous ligament and triangular fibrocartilage, resulting in bic ompartmentalization of the radiocarpal joint. In all of the 7 wrists, having no history of trauma, the septums were suspected to be of conge nital origin. The histopathology of the septum in 1 cadaver wrist show ed a fibrocartilaginous structure. Two types of radiocarpal joint bico mpartmentalization were identified by arthrog raphy. Type 1 (2 wrists) had a septum with normal (intact) lunotriquetral interosseous ligamen t, and type 2 (5 wrists) had a septum with a communicating defect of t he lunotriquetral interosseous ligament. The septum is most likely a c ongenital malformation caused by a disturbance of the vacuolization of the mesenchymal mass between the forearm and carpus.