Navicular disease once was called ‘the last resort of the diagnostically destitute (practitioner),’ based on the syndrome’s ambiguous symptoms and the practitioner’s inability to isolate definitely the source of the horse’s pain. In the 1980s, navicular disease was believed to be the most over-diagnosed lameness in American horses. The reason? You could never really be sure what was causing the lameness. Symptoms were lumped together; owners demanded a name to put on the lameness.

That was all before the renaissance in foot studies, which has given us the ability to experiment with shoeing, nutrition, joint injection, and pain medication to give the horse a path out of the pain. Most people point toward better quality machine-made shoes–with longer heels, wider webs, and better overall support–as being the single largest contributor to the increase in soundness in our horses. To that, I’d add the availability of many more highly skilled farriers at work on our horses. They are providing improved hoof balance and remedying those acute toe angles that place the navicular bone in an ouchier-than-need-be position in the foot.

For the purposes of this column, let’s refer to the problem as �navicular lameness,� meaning that the horse shows signs of lameness in the caudal (back) part of the foot when hoof testers are applied. Diagnostic nerve blocks also can isolate the source of pain to the back of the foot.

That is still pretty vague; navicular disease has many different definitions, depending on to whom you talk, and on what day. Technically, what we are looking for in these cases is podotrochleosis, a specific aspect of �navicular disease� centered in the area of the tendon/bursa/bone sandwich at the point where the deep flexor tendon curves to its point of attachment at the base of the coffin (P3) bone