Horse With Curved Back

The thoracic spine (middle) and lumbar spine (end or tailbone) of horses are typically a very pronounced curve, forming what’s clinically called a “U” shape. While this curved back or lordosis may look alarming, the horse is often healthy and function normally. But if you were to see a dog or human with an extreme spinal curvature, they could be at risk of paralysis or impaired body movement. Horses, however, are incredibly flexible, and while they can be more prone to developing a crooked or bowed back as they age, the abnormality is rarely a serious threat to health or performance.

A horse’s topline curves as it rises and falls, and the resulting undulations are very noticeable to observers. The curve is produced by finlike projections on the upper surfaces of the vertebrae, called dorsal spinal processes. These processes are longest at the withers, shorter under the saddle and then longer again toward the hips. As the horse grows from infancy to maturity, these processes grow taller, creating a deeper and taller back contour.

Horses with long backs are a breed of choice in many competitive equine sports, as their conformation allows them to carry riders more comfortably. In addition, a long back is more resilient than a short one against muscular strain and is less prone to becoming lordotic.

But that conformation trait is also a risk factor for the development of swayback, and many horses with long backs develop it over time. This is because of the extra stress that is placed on the longissimus dorsi muscle — the major contributor to the horse’s topline — when a horse tries to achieve high levels of collection. To do so, the horse has to lift his withers and tuck his croup, pulling the sternum and pelvis close together and compressing the abdominal contents against the back.

When the ribs and heartgirth move inward as this is happening, they compress the muscles of the loin and the back and stretch those of the withers and lumbar spine. This creates a more pronounced tuck and an even greater curve in the topline. When this is combined with a shallow or flat girth spot, a horse’s back will seem more curved and crooked than it actually is, because the saddle must sit correctly to allow the horse to perform at its best. This is why assessing your horse’s back contour on a regular basis is important. It can help you determine if it is deep enough to support the rider, and if not, how you can correct it. If you are unsure whether your horse is in the ideal girth spot, try standing above them or behind them on a block, and seeing where their billets fall. They should be about three fingers’ width behind the point of their girth. This is the perfect position for most Western saddles and about four fingers’ width behind the point of a English saddle.