[Luxations and subluxations of the scaphoid bone]

The rare occurrence and the difficulties in diagnosis make partial and total luxations of the scaphoid to a problematic chapter in hand surgery. The main part in diagnosis lies in the correct interpretation of the X-ray pictures from which the different formes of displacement may be recognized. These include isolated luxations of scaphoid in palmar, radial or dorsal directions, varying degrees of scapho-lunate subluxations and luxations and the special type of isolated subluxation of the scaphoid bone. In the first part of the paper the diagnostic criteria and in particular the radiologic signs are described. Most important is the recognition of the alteration in the shapes of the scaphoid bone due to its tilting on several axes and the overlapping of its outline with that of the adjacent bones. The displacement of the whole carpal region can extend as far distal as the metacarpals. A diastasis of the scaphoid and lunate is typically due to rupture of the ligaments between these bones and the radius.