The Diagnosis of Lameness in the Horse
  by Robert N. Oglesby DVM

Note: if you have a lame horse and do not know why, this is an excellent place to start.

Lameness is defined as "a deviation from the normal gait or posture due to pain or mechanical dysfunction". We recognize lameness because there is a change in the way our horse stands, walks, trots, or canters. Usually lameness is the result of pain, but not always. Mechanical factors and abnormal nerve function causes several well-defined problems with the horse's gait. The steps necessary to arrive at a firm diagnosis for the cause of a lameneess are:

1. Identifying a clear symptom of lameness.
2. Localizing those symptoms to the diseased leg or legs.
3. Localizing the area of the leg that is diseased.
4. Identifying the nature of the disease

Only when these steps are followed carefully is it possible to arrive at a correct diagnosis. Sometimes the steps are as easy as:

Steps 1 and 2: the horse will not bear weight on the right leg.

Step 3: The foot is as hot as a iron.

Step 4: Examination of the foot with hoof testers finds a sore spot that when pared into exudes puss.

But often the symptoms are such that they don't immediately lend themselves to identifying which leg is involved or even whether it is pain in the leg or foot responsible for the problem. This article takes each of the steps of diagnosing lameness and explains them so that you can recognize the changes associated with lameness, how to determine which leg is lame, how to localize the lameness in the leg, and then how identify the cause. Links to specific causes of lameness are then provided.