PrintI have to confess, I like objectivity. I like sports where they keep score based on things like if the horse did or did not knock down the fence, or if the goal was or was not scored. The more subjective sports, where winning is based on whether or not the contestant appealed to the judge’s sense of how things are supposed to be, (like, say, gymnastics, or figure skating), make me a bit nuts.
Lameness exams can run the gamut between objectivity and subjectivity. On the one hand, sometimes you have a horse that won’t put his foot on the ground. There’s a nail in the foot. Voila, objective evidence of the problem. Pull the nail, bandage the foot, and in a few days the problem is solved. Everyone is happy.
On the other hand, sometimes you have the horse that isn’t switching its leads properly, or isn’t going round enough, or is in some way not performing up to its owner’s expectations. In these cases, invariably, owners and trainers will conclude that something is wrong with the horse. And, sometimes when I examine that horse, I find something wrong and treat accordingly.
But not always. Sometimes I trot that horse up and down and try to see where the problem is. I may flex a limb, make the horse go in circles, or do something else to try to make him show me where he’s lame, and sometimes I still can’t find much of anything at all. There might be some change after a local anesthetic block; maybe then the problem will seem to switch legs. Maybe I’ll take some X-rays, or advise a bone scan; sometimes even those tests don’t let me know what’s up. (Maybe the horse is normal, but, for some reason, some owners and trainers don’t like to be told that.) After all the time, effort and expense, I end up scratching my head. And, to be frank, when your veterinarian is scratching his head, it’s not a good confidence-builder.
The thing is, when it comes to lameness, we veterinarians are mostly trying to find something objective on which to hang our diagnostic hats. We’re looking for a bobbing head, a lifting pelvis, a funny leg swing, or some other clue that something is wrong. Happily, since horses tend to be fairly predictable in the way that they move when a leg hurts (e.g., “head up on the bad leg, down on the good leg”), we can often assert, with some confidence, based on patterns of head, pelvis and leg movement, that we know in which leg a horse is lame.
Even though that’s an objective approach, the problem is that the human eye isn’t very reliable in recording and processing information. As a result, studies have shown that veterinarians tend not to be very consistent in their observations of lame horses. That is, one veterinarian may think a horse is lame in one leg, whereas another might pick another limb (or limbs) as the culprit. That happens, because, among other reasons, we measure the things that we’re looking for with our eyes.
Everyone should be willing to admit that their eyes are fallible. People see mirages, they have hallucinations, and they can be fooled by optical illusions. They can see what they want to see. And, even when they work perfectly, eyes are not nearly as good at recording optical information as mechanical devices; that’s why you like to take pictures!
