Investigation was made on the X-ray tube voltage and the tube current which were necessary for lateral oblique radiography of the shoulder joint of the horse in the standing position. Then examination was carried out to reduce the scattering beam effectively with a lead cone. As a result, it was possible to get radiographs available for diagnosis. (1) Movement was reduced in a horse administered intravenously with 0.6-0.8mg/kg of xylazinehydrochloride. The horse was restrained in a stock with the troubled forelimb stretched. The central ray was directed to the end of the cervical vertebra and lateral radiographs were taken from oblique anterior to posterior. (2) The X-ray tube voltage used was 80 kVp. It was enough for the radiography of the equine shoulder joint. A fine radiograph was taken when the tube voltage was 100-110 kVp and the tube current was 100-300 mAs. In this case a single Lisholm-Blende at a grid-ratio of 10:1, the focus-film distance used was 120cm. (3) Fine radiographs were taken by use of a lead cone to reduce the scattering beam. (4) Significant damage was found in 8 cases (3 cases of fracture of the scapula, 4 cases of fracture of the humerus, and 1 case of osteoperiostitis of the shoulder joint). It would account for the clinical signs of forelimb trouble in 40 cases.
