Once confirmed that a horse has a joint problem, injections may be recommended to prevent further damage and provide comfort and relief to the horse while attempting to pinpoint the exact location of the pain. (vetmed.tufts.edu)
However, as we know to be the case in so many injuries, the problem is not always at the location of pain. (exclusive.multibriefs.com)
3) Injury: This is a tricky one, but if you are concerned about an injury, but can not see the location of the pain or you need a clean area to examine, it's time for a bath. (petsinthecitymagazine.com)