[The radiologic image of the normal equine tarsus]

Normal radiographs of hocks were analyzed for 270 horses (3 views for each hock). They were mainly from young and sound horses. For such animals, the mean number of abnormalities found was 2 to 4.5 for each picture. The mean dimension of certain tarsal bones was measured; geldings had greater bones than mares. An increase of reactions at the origin of the M. interosseus was seen with the age. It was possible to demonstrate that Medichrome films increase the number of discrete abnormalities to be found; this is of particular value for purchase examinations of young horses. The direction of the central beam (angle) is important in order to get symmetrical pictures; a minimal change in this angle can show or hide discrete abnormalities. A description of the normal radiographic anatomy of the equine hock, and its principal variations, is given.