Program for the Assessment of Veterinary Education (PAVE) Practice Test

OCD in dogs most often affects the elbow joint, with lesions typically on the medial aspect of the humeral capitellum (the inner side of the distal humerus that bears weight). This region is most subject to abnormal endochondral ossification during growth, leading to a cartilage flap and possible fragmentation if the abnormal bone fails to ossify properly. Because of that, elbow Lameness with joint signs is the classic presentation.

The example site listed in the other region refers to the shoulder area, which is not the usual location for canine OCD. While OCD can occur in other joints like the hip or stifle, the elbow—specifically the medial capitellum—is the most common. This helps explain why the elbow is the focus when diagnosing canine OCD on radiographs and during clinical exam.