dorsoproximal-dorsodistal projection of the distal carpal bones in horses: an evaluation of different beam-cassette angles

To estimate the extent of the third carpal bone (C3) visible for evaluation in the dorsoproximal‐dorsodistal oblique projection of the distal row of carpal bones, 13 forelimbs collected at post mortem from 7 horses were examined radiographically. The limbs were frozen with the carpal joints flexed then radiographed using fixed beam‐cassette angles of 15° to 45°, at 5° intervals. The influence of beamcassette angle on; the depth of the proximal articular surface examined, the radiographic appearance of C3 and the assessment of subchondral sclerosis was evaluated. Beam‐cassette angles of 25° to 40° produced subjectively acceptable radiographs and did not appear to influence assessments of sclerosis. The mean depth of the examined proximal articular surface of the C3 increased significantly with each 5° increase in beam‐cassette angle up to 40°. The use of beam‐cassette angles >35° is recommended for the DPr‐DDiO projection.