‘The history of mankind is carried on the back of a horse…’
Author unknown

Throughout history, the horse’s back has carried soldiers into battlefields, monarchs through their kingdoms, and messengers across the land. These days, your horse’s back carries you down the trail, around the show pen, and over obstacles.

If your horse’s back is weak or sore, chances are the ride won’t be a pleasant one for him. He’ll probably pin his ears and swish his tail when he’s working. If it really hurts, he may simply plant his feet and refuse to move at all. In fact, back pain is probably one of the most common causes of bad behavior and training challenges with a horse. And if your horse isn’t happy, no one’s happy!

I’m going to teach you about your horse’s back, and how to keep it healthy as he ages. I’ll begin by giving you an overview of back anatomy, and will describe the most commonly diagnosed back problems you’re likely to encounter.

Then I’ll divide your horse’s life into three important phases: his youth, his prime, and his slow decline as he reaches his golden years. During each phase of your horse’s life, he’ll experience different physical challenges—and these challenges can affect his back. You’ll learn what these challenges are, and what steps you can take to combat them through the ages.

Basic Back Anatomy
The equine back, consisting of bones, ligaments, cartilage, and muscles, is far more complex than what you can see with your naked eye. The vertebral column can be divided into five sections: cervical, thoracic, lumbar, sacral, and coccygeal. The sections that make up your horse’s back include the 18 thoracic and six lumbar vertebrae, and extend from just in front of his shoulder to his pelvis.

The thoracic vertebrae are constructed with a tall dorsal spinous process that extends up to form his withers and the ridge of his spine, and provides attachments for the muscles of his neck and forelimbs. Each thoracic vertebra is connected to a rib. The lumbar vertebrae are wider rather than tall, with processes that extend on either side to provide attachments for muscles of the pelvis and hind limbs.

Each vertebral body has a convex surface on the forward edge and concave surface on the back edge that fit together with a cartilage disk between them to form the joints of the spine. In addition, each vertebra has a process on either side that extends in a forward direction and another that extends in a backward direction. These processes connect to one another with a small, fluid-filled joint between them. This junction is called the articular facet.

The spine is supported along your horse’s topline by the supraspinous ligament that runs the entire length, from his poll to his croup (in his neck, this ligament is called the “nuchal ligament”). The muscles of his back are then divided into two major categories, the “long back muscles,” and the “short back muscles.”

The primary long back muscle is the longissimus dorsi. It originates from the lower cervical vertebrae, and extends along the full length of his back to insert on portions of his sacrum and pelvis. The primary short back muscles are the multifida, tiny muscles that are deeply placed along the spine to help support the vertebrae.

The rectus abdominis and internal and external abdominal obliques, or muscles of your horse’s belly, also play an important role. They attach to the sternum (chest bone) and ribs, and provide a sling for his viscera or internal organs. Without these belly muscles, the weight of those internal organs would put enormous pressure on your horse’s back.

When Things Go Wrong
A wide variety of different things can go wrong with your horse’s back. Back problems are difficult to diagnose, and not well understood. They’re also challenging to treat. The following are some examples of the more common equine back problems you’re likely to encounter, ranging from mild to more severe.

Pressure/friction bumps. You’re most likely to see these hard lumps in locations on your horse’s back where there’s excessive pressure from the saddle. Although they typically don’t cause him any pain, these bumps tell you that something isn’t right. If you take steps to address your problems when pressure bumps first appear, you’ll reduce the chances of a more serious problem down the road. Check your saddle fit, and consider some type of padding that distributes pressure across the back and minimizes friction. A sheepskin-lined, pressure-distributing pad often can help.

Muscle pain. The muscles of your horse’s back can become painful for a variety of reasons, ranging from a lack of strength and instability of the spine to poor, unbalanced riding or an ill-fitting saddle. One thing is certain: If the muscles of your horse’s back are sore, he’s at increased risk for more serious bone-related problems. Correct riding and conditioning and properly fitted tack are key. Acupuncture or bodywork can be beneficial for treating sore back muscles when they appear.

Kissing spines. Impinging dorsal spinous processes or “kissing spines” are a fairly common abnormality, more likely to occur in a horse with a weak or “dropped” back. As the back drops, the joints between the vertebrae extend, bringing the dorsal spinous processes closer and closer together until they eventually come in contact with one another. The condition is possible in horses that experience no pain at all. However, if this condition is associated with inflammation (heat or swelling), it can be extremely painful, especially if it is combined with a soft tissue injury. For some horses, nuclear scintigraphy (a bone scan) of the area will be the most reliable way to make an accurate diagnosis of a significant case of kissing spines. If kissing spines are truly a problem, they’re often difficult to treat, and can easily become a chronic, performance-limiting problem.

Articular facet arthritis. Weakness and instability of your horse’s spine eventually can lead to arthritis in the small facet joints between the vertebrae. Arthritis in these tiny joints will cause the back to become stiff and painful. Nuclear scintigraphy, radiographs, and ultrasound may all play a part in making a diagnosis, which can be difficult. And treatment is challenging; like kissing spines, back arthritis easily can become a chronic performance-limiting problem.

What’s the best answer for managing your horse’s back? Recognize and take care of problems that are likely to arise throughout his life—before they progress to something serious.

Stage 1: The Younger Years
The challenge: Immaturity. Most horses are started in work when they’re still very young. A 2- or 3-year-old hasn’t finished growing and most likely isn’t strong enough to handle rigorous training demands.

How to meet it: Be conscious of your horse’s maturity level, and don’t ask for too much too soon. Tailor his work schedule when he first starts under saddle to include slow, careful conditioning work. And don’t expect an 800-pound youngster to carry a 250-pound man on his back. Keep the load on his back to 20 percent or less of his body weight. That’s 200 pounds of rider and tack on a 1,000-pound horse.

The challenge: Changing shape. When your horse first starts in work, he’ll muscle up and change his shape dramatically as he gains strength. These changes mean his saddle fit is likely to change rapidly, and an ill-fitting saddle will make him sore.

How to meet it: Check saddle fit, and make adjustments frequently (two or three times each year) when your horse is young.

Stage 2: At His Prime
The challenge: Developing muscle. When your horse is mature, his muscling and body shape will continue to change. The contour of his back may become flatter as muscles grow, and even the slope of his scapula can increase as he begins to carry more weight on his hindquarters and less in front. Saddle fitting can continue to be a problem.

How to meet it: Continue to monitor your saddle fit, and plan on making adjustments at least annually.

The challenge: Hard work demands. When your horse is in his prime, he’s likely to be working extra hard. All that time with a saddle on his back puts him more at risk for pressure/friction bumps and muscle soreness. He’s also more at risk for other musculoskeletal injuries, and lower limb lameness can be associated with secondary back pain.

How to meet it: Always pay attention to the condition of your horse’s back. Keep an eye out for pressure bumps, adjust your padding as necessary, and consider making acupuncture or bodywork a regular part of your horse’s overall management. Detect, diagnose, and treat lower-limb injuries as soon as possible to avoid secondary effects on his back.

Stage 3: The Decline
The challenge: Older horses become less efficient at metabolizing protein, which is a necessary building block for muscle. Strong, healthy muscles are important for supporting your horse’s back.

How to meet it: Pay close attention to the protein content of your horse’s diet. Whereas a younger horse needs only 9 to 10 percent protein in his daily ration, your old timer should have a minimum of 12 to 14 percent. Unless your older horse has a specific medical condition (such as kidney failure) that means his protein intake should be limited, it’s better to feed a little too much protein than it is to feed too little. Consider adding a senior feed ration to his daily diet for a bit of extra, high-quality protein.

The challenge: Your older horse may have dental issues. If he does, he can lose up to 40 percent of the nutrients in his hay because of inadequate chewing. If he’s missing nutrients, his muscle and other supporting tissues are likely to suffer.

How to meet it: Be sure to schedule a dental exam every year, and perform whatever procedures your vet thinks are necessary to maximize dental health. If your horse has dental problems that can’t be fixed, a senior feed ration can help again, as these rations are specifically designed for easy chewing.

The challenge: Cushing’s disease. Many older horses develop this metabolic disease that leads to muscle atrophy (and dental problems!). Once again, a loss of muscle strength means a loss of back support.

How to meet it: Test and treat for Cushing’s disease. If you notice any signs typical of this disease, such as a long or even curly hair coat that doesn’t shed, ask your vet whether testing your horse for Cushing’s would be advised. If your horse tests positive, treatment with the medication pergolide can help minimize symptoms—and will slow down the progression of your horse’s muscle atrophy.

The challenge: Lack of use. As your older horse eases toward retirement, his work demands are likely to decrease. When he’s working less, his muscles will weaken and his back will lose support.

How to meet it: Don’t ignore the importance of conditioning for your older horse. Long walks and careful regular work can help keep his fitness level solid, without causing problems.

The challenge: Collagen breakdown. Collagen is an important substance that makes up the “scaffolding” that provides integrity to tendons and ligaments—especially important when it comes to the supraspinous ligament of your horse’s back. Collagen breakdown is a known event with aging. Picture the older horse with his drooping lower lip (or the old lady with her sagging skin)—both the result of collagen loss.

How to meet it: There’s not a lot you can do to protect collagen directly. However, by supporting your horse’s muscles with proper nutrition and regular exercise, you’ll minimize stress and breakdown of the supporting ligaments.