The horse is an amazing animal. Anyone who competes on a horse is drawn to them through their essence and athleticism. Their anatomy and structure are equally as fascinating.
The horse’s back is sometimes overlooked in its contribution to movement. Connecting his front end to his rear end, the back carries the rider while performing athletic feats to the best of his ability. As competition gets tougher and more competitive every day, looking at the whole horse is imperative to gain an edge.
Understanding the horse’s anatomy will equip you to handle different situations, whether it be a mild soreness, decreased performance, or a significant back issue.
Now, while their spine does not allow them to slump over in their office chair and stare at a screen for hours on end, horses have the same degrees of movement as humans.
Horses can flex and extend their spine. Think about changes in the spine when a horse really rounds their back to collect verses when a horse throws their head in the air high and their back really sinks down. Horses also have the ability to rotate and side bend through their spine.
The horse’s spinal anatomy is similar to our own. It is split up into cervical, thoracic, lumbar, and coccygeal vertebrae.
Not only are our spines similar in number; they are similar in shape as well. The bony aspect that sticks up is called the dorsal spinous process. One of the main purposes of the dorsal spinous process is to be a lever for muscular and soft tissue attachments. The withers are the area of the spine where the dorsal spinous processes are the longest.
The cervical spine is the most mobile region of the spine. While humans and horses have the same number of vertebrae in this region, horses have one of the longest necks with a relatively heavy head. Due to these factors, the horse’s cervical spine is located in the lower region of their neck. The horse’s neck is composed of strong massive ligaments and muscles.
The start of the thoracic vertebrae is in between the shoulder blades. The withers are formed by the T2-T8 vertebrae. For best saddle fit for the spine, the saddle should sit between approximately T8-T18. The downward slope of the withers, where it meets the back, is approximately where the T8 is located. With a western saddle, placing the front concho behind the shoulder blade is an easy way to start getting the saddle placed at T8. Finding T18 can be done by finding the last rib and going directly above.
One of the anatomical reasons that the horse is so athletic is the space between these spinous processes. Just think about when a horse stops on his rear end and really tucks it up under himself, rounding his back. This movement happens through a large portion of the thoracic spine up until around the T11 vertebrae. At this location, space between the spinous processes decreases and continues through the loin. The space narrows and sometimes overlaps, the spinous processes normally do not touch. However, kissing spine is a condition that can develop in this area. The close proximity of the spinous processes causes narrowing or false joint formation of the vertebra.
Moving along through the spine towards the tail, we arrive at the sacroiliac joint. The sacroiliac or SI joint is where the spine and the hind end or pelvis of the horse meet. There are a lot of forces and factors at play in the function of this joint in both the horse and the human. There are a lot of propulsive forces from the hind end that move the horse forward through this joint.
Horses that are prone to issues in this area include those performing in high-impact events such as barrel racing, tie-down roping, three-day eventing, show jumping, reining and team roping. The SI and pelvic areas will be the focus of another blog post.
The horse’s tail is composed of the coccygeal vertebrae which is analogous to our tailbones. Depending upon position in the tail, these vertebrae can look quite different from one another. The spinal cord tapers off through the sacral region of the spinal column. It tapers off into a series of different nerves that innervate parts of the hind end and tail region.
Understanding the bony anatomical structure can give the rider a good start to an anatomical foundation. After all, we ride on our horse’s backs! Understanding the bony make-up will provide the building blocks that will serve as the foundation for our understanding about our horse’s health. Helping our horses stay healthy and perform at a top level is an utmost priority.