[Luno-triquetral angle and dislocation of the wrist]

The mediocarpal force, determined by the distal articular surface of both, lunate and triquetral bones, abuts against the double bolt, composed of the scaphoid and the radial styloid process. An important wrist trauma can rupture this bolt and cause a proximal and lateral translation of the distal carpal row. This situation may present under 3 forms: fracture of the scaphoid bone and midcarpal dissociation; fracture of the radial styloid process with scapholunate dissociation; scapholunate dissociation, associated with a dorsal radiotriquetral ligament rupture and medial translation of the lunotriquetral block. Experimental and clinical illustration of this process, discussion and treatment.