A quick review of your horse’s back
Your horse’s back has three distinct sections called the Thoracic, Lumbar and Sacral regions. Each part of the horse’s back needs to be aligned correctly to help your horse move easily and efficiently.
The Thoracic region
The Thoracic region is composed of 18 vertebrae which attach to the ribs, forming the trunk of the horse. The thoracic region of the equine back is rigid and inflexible compared to other mammals and begins right behind the withers.
This portion of the back carries the saddle and rider due to the shape of the interconnecting facets of the thoracic vertebrae that restrict dorsal (upward) and ventral (downward) movement of the spine. Horses seldom have disc issues because the thoracic region is very inflexible and the discs are narrow, compared to human’s discs.
The Lumbar Region
This area is composed of 6 vertebrae which are flatter, wider and heavier than those in the thoracic region. The spinous processes of the vertebrae become smaller and the transverse processes become longer. The shape of the lumbar vertebrae permit more lateral, dorsal, and ventral flexion of the spine in this region.
The Sacral Region
The area where the lumbar vertebrae connect with the sacral vertebrae is called the Lumbar-Sacral Junction. Flexibility in the lumbar-sacral junction is essential to achieve collection because it allows a horse to bring his hind legs underneath him and drive off the power of his “engine”.
The sacral vertebrae include the vertebrae in the horse’s tail, which help with balance. Throughout the spine are nerves that carry messages from the brain of the horse to the rest of the body.