In a Galeazzi fracture-dislocation the displaced radial shaft fracture is associated with a dislocation of the ulnar head at the distal radioulnar joint (DRUJ).
These are classified by AO/OTA, according to the morphology of the radial fracture, with qualifier (g). For example, the illustration shows a 2R2A2(g).
Most often, the dislocation of the ulnar head is posterior, but very seldom it is anterior (as shown in the x-ray).
Simple fractures are often the result of indirect mechanisms, such as a fall onto an outstretched hand, sporting activities, etc.