Assessment of Back Pain

Quantifying the degree and precise site of pain in animals always has been difficult. This is complicated further because the major clinical sign in many horses with a back problem is impaired performance rather than pain. On the other hand, many horses appear to perform satisfactorily despite some low-grade back pain. To add to this confusion, some horses are naturally sensitive and resent being palpated along the back, which might be wrongly interpreted as a sign of pain.

Cold Back

This term describes hypersensitivity over the back with a transient stiffness and dipping of the spine as the rider mounts. There usually are no other clinical signs, although in severe cases, the horse might buck or rear at first. This initial stiffness wears off within a few minutes and causes no effect on performance. Whether this condition actually is associated with back pain or merely a matter of temperament is not clear.

Many of the difficulties in diagnosing back problems would be solved if some meaningful criteria could be established for assessing and quantifying back pain. The back has a system of nerve endings that are particularly sensitive to tissue dysfunction. They are referred to as “nociceptive receptors” and are represented in the back by arrangements of unmyelinated nerve fibres. In normal circumstances, this receptor system is relatively inactive, but it is stimulated by mechanical or other damaging forces applied to the tissues containing the nerve endings. Primary back pain results, therefore, from trauma or irritation of these nerve endings