In a closer look at the standard forelimb flexion test, researchers from Ireland and the Netherlands found that any forelimb lameness detectable with this method generally shows up in the fetlock joint. They also found that the exam can render a false positive result in this joint (indicating that the horse is lame when in reality he is not), depending on how much force is used when conducting the exam.

During a flexion test, a veterinarian flexes a horse's legs one at a time, either stretching or compressing different areas of the legs. Once a leg has been flexed, the horse is trotted in a straight line and the veterinarian watches for signs of lameness. Flexion tests are most commonly used in prepurchase and lameness exams.

René van Weeren, DVM, PhD, Dipl. ECVS of Utrecht University and his colleagues indicated in their recent study that the fetlock joint is the most important area to examine for problems if a horse displays a positive result in a forelimb flexion test focused on the lower, or distal, aspect of the leg.

"The flexion test does not tell much about the hoof and its internal structures, or the pastern region," relayed van Weeren. "If the test is positive, the pain-causing factor will likely be in (or around) the fetlock