Radiographic signs of osteochondritis dissecans of the lateral ridge of the trochlea tali in the dog

Osteochondritis dissecans lesions of the lateral ridge of the trochlea of the talus occur infrequently and are difficult to diagnose. They occur mainly in the proximal or proximodorsal section of the lateral ridge of the trochlea and are best seen in the plantaromedial-dorsolateral oblique projection (with the X-ray beam angled 30 to 45^o from the vertical), and in the fully flexed and extended mediolateral projections. The flexed dorsoplantar projection using a horizontal beam is also useful.