Q.  I have a 4-year-old hunter who has become lame in his hind end. He routinely goes over 2′ 6" jumps, but never anything larger. Being only 5’3", I do not think that my problem is the weight I am asking him to carry. There are no obvious problems with his hind end that I can see. What types of tests can I expect to be performed on him to determine his lameness?

A.  Hind end lameness affects different breeds and disciplines in various ways. A Thoroughbred, Standardbred, or Quarter Horse is going to be affected differently depending on its use. With any lameness exam, however, a case history of the horse should be compiled. Significant to the case is the age of the horse, the type of work the horse does for a living, the events in which the horse has competed recently. Was there some special event that was associated with the lameness, or did the lameness just covertly become part of what was happening to the horse? Ligament problems or fractures should be investigated if the lameness showed up after an event that might have caused stress to the hind end.

Obtaining clinical signs is next on the list after the horse’s history has been organized. In order to get clinical signs, the veterinarian performs a physical exam in which any abnormalities of the limbs are noted and taken into account. Heat, pain, and swelling–the cardinal signs of inflammation–are a part of the physical exam. Once a physical exam has been performed, and any inflammation is noted, then a full-fledged lameness exam might be performed if further examination is necessary to determine a diagnosis.

In a lameness exam, the horse is trotted on a straight, solid surface. He is turned clockwise and counter clockwise on a longe line to see if the lameness changes when the direction is changed. This will help localize the area where the lameness originates. A flexion test also will help determine the area of lameness. The first flexion test performed is on the ankle, with the following flexion test being a hock/stifle flexion, so named because the two parts have to flex together, given the anatomy of the hind limb