HOW TO TAKE AND INTERPRET RADIOGRAPHS OF THE YOUNG PERFORMANCE HORSE
Fig. 8. A and B, Typical poor positioning for caudocranial view. Beam is directed horizontal rather than proximal to distal result- ing in failure to achieve separation to evaluate femorotibial joint spaces.
should be directed on the femorotibial joint, 10 cm caudal to the cranial aspect of the limb. The x-ray beam should be directed horizontal to the ground or slightly proximal to distal 10°–15° (Figs. 9–13).
The patellar skyline view is taken with the stifle flexed and the tarsus either flexed or extended. The cassette is held approximately horizontal with its caudal edge against the cranial aspect of the tibia, centered just proximal to the tibial crest. Depending on the horse, the beam angle may range from a proximal 10° lateral-distal medial oblique direction to a 30°–40° proximocranial-distocaudal direction. Adducting the flexed limb may facilitate positioning by rotating the stifle outwards. The indications for the patellar skyline view in- clude assessment of a suspected patellar fracture,
and to better assess a known patellar fracture or suspected osteochondrosis of the patella or lateral trochlear ridge of the femur (Figs. 14 and 15).
Flexed Lateromedial View
Positioning is similar to the lateromedial view. The degree of flexion of the stifle can vary from just slightly flexed with the horse resting the toe on the ground to moderate flexion. The beam is directed horizontal, centered on the patella (Figs. 16 and 17). The indications for the flexed lateromedial view in- clude a better assessment of the apex of the patella, to
Fig. 10. Line drawing of a 30° caudolateral-craniomedial oblique view. The view is taken primarily to evaluate (1) site of typical subchondral cyst in medial femoral condyle; (2) typical area for OCD of the lateral trochlear ridge of the femur; (3) medial ridge of the femoral trochlea; (4) area of the extensor fossa; (5) tibial tuberosity; (6) medial femoral condyle; (7) lateral femoral condyle; (8) spine of the tibia; (9) medial condyle of the tibia; (10) attach- ment site for the biceps femoris and lateral patellar ligament. Adapted from O’Brien.3
Fig. 9. (A) Positioning for 30° caudolateral-craniomedial oblique view. (B) Apparently normal 30° caudolateral-craniomedial oblique radiographic view of a mature Thoroughbred gelding.
