
Overriding Dorsal Spinous Processes (ORDSP), commonly known as Kissing Spine, tends to occur where the saddle sits. ORDSP can occur in any breed of horse, although it is more common in Thoroughbreds, Warmbloods, and other performance horses that are 5-10 years old.
The Spine:

Five types of vertebrae exist in a horse’s spine: cervical, thoracic, lumbar, sacral, and coccygeal (Fig. 1). With an average of fifty-four vertebrae, a horse’s individual vertebra is labeled with the corresponding type and number to avoid confusion. The eighteen Thoracic vertebrae are located in the withers and part of the back, with T1 at the withers. Every Thoracic vertebra is attached to a set of ribs and has a vertical piece of bone at the top called a dorsal spinous process.
ORDSP Explained:

A horse can be diagnosed with Kissing Spine when the dorsal spinous processes are too close, touching, or in severe cases, overlapping (Fig. 2). When the horse moves, the spinous processes rub together and cause pain. Typically Kissing Spine occurs between the T13 and T18 vertebrae. Those vertebra are naturally closer together where the withers and back meet. The rider sits directly on top of the vertebrae as well.
Diagnosis:
Clinical signs of Kissing Spine can include decreased range of motion when asking the horse to flex and stretch. More noticeable behavior changes can occur as well, such as bucking, rearing, and girthiness. A horse may be sensitive when a saddle is placed on his back and painful to palpitation along the spine. He can even have intermittent lameness on several legs. In addition to observing clinical signs, a vet will need to take X-rays to make a proper diagnosis.
The Why:
So what causes Kissing Spine? Many believe that Kissing Spine is likely to occur in a horse that was ridden too early, however there isn’t any data to support this claim. Even horses that haven’t been under saddle can be diagnosed, which tells us that Kissing Spine may have more to do with genetics. However, it is more likely a riding horse will develop an issue than a horse that hasn’t been ridden.
Unfortunately, research shows that riders can be part of the problem. Kissing Spine can develop as a result of poor saddle fit and improper training. Other health issues can cause the horse to use his back incorrectly to compensate for pain elsewhere, which can also lead to Kissing Spine.
Treatment:
There are several options to treat a horse with Kissing Spine, depending on the severity. A vet may suggest chiropractic, acupuncture and shock wave therapies for mild cases in addition to strengthening exercises. If the horse is still in pain, anti-inflammatories can be injected into the spine to reduce pain. The worst cases may require surgery, of which there are two options: a section(s) of spinous process can be removed or the ligaments between each affected spinous process can be cut. Although a more expensive surgery that requires extra recovery, removing a spinous section(s) has proved to be more successful.
Prevention:
The good news is that there are exercises riders can do with their horses that can help prevent Kissing Spine (assuming the horse isn’t predisposed). To strengthen the back muscles and keep the back from hollowing, the horse must engage his core. Once he does, the withers and the back rise, flexing and separating the spinous processes. The back muscles become stronger and more stable so the hindquarters will lower, the pelvis will tilt, and the horse can step underneath himself.
There are several core-strengthening exercises a rider can do with the horse on the ground.

- Core Crunches: Check that the horse’s front feet are square before starting the exercise. With your fingers, push up into the chest area between the horse’s front legs until he pulls his chest up toward his withers, away from the pressure. Hold for five seconds and repeat (5 reps total). Then do a set with pressure on the girth area and another set in the middle of the horse’s belly. You will see the horse’s spine and ribs rise up as he engages his core to perform the exercise (Fig. 3).
Fig. 4: Horse’s spine is higher in the right picture while doing the hip tuck, and his ribs have moved up and back toward his spine. - Hip Tucks: Check that the horse’s hind feet are square before starting the exercise. Standing slightly to the side of the horse’s hindquarters, apply pressure with your fingers on the spine a few inches above the tail. You should see the horse tuck his hips underneath himself and put more weight on his hind end (Fig. 4). Repeat (5 reps total).
Fig. 5 - Stretches: Check that the horse’s front feet are square before beginning the stretches. With a treat, encourage your horse to stretch his neck down until his nose is between his front hooves. Hold for five seconds. Repeat at knee level and encourage him to stretch as far between the legs as he can (his nose should be past the front legs). You should also have the horse perform the following stretches on both sides of the body: the nose to the shoulder, then the girth, the stifle, and the hock, holding each for five seconds with breaks in between (Fig. 5). These stretches should be done before and after a ride.
- Hill Work: Walk the horse up and down the hill several times. Walking up the hill is very important because the horse must keep his hind feet underneath him to propel himself up the hill without losing his balance. If your horse is already able to back up properly, you can have him start backing up the hill. He will have to lower his hindquarters to take the weight off his front feet and step backward. Both exercises can be done under saddle, but it’s probably best if you start in hand.
- Poles and Cavaletti: A well-known exercise that engages the horse’s core and lifts his back is working over poles. This can be done in hand or under saddle, at the walk trot and canter.

There are plenty of exercises to do under saddle as well! Every exercise should be started in a “long and low” frame to allow the back to round as the horse reaches for the bit. The horse must be straight and balanced before you can even think of collecting the gaits. When your horse is strong enough to come into a higher frame and begin to develop collection, you will know his core is engaged when the front end lightens, the hindquarters come underneath him and you feel as though his back is rising to meet you (Fig. 6). His back should be rising to support the rider, rather than the rider forcing himself into the horse’s back. *Note that without proper core strength of the rider, collection cannot be achieved even if the horse has proper muscling.*
- Walking on a 5-meter circle with plenty of bend until the horse lets go of the shoulder and neck will help unlock the front of his body and help him to stretch his back.
- A leg yield in a deep overbend allows the hips to unlock and move on their own. In fact, leg yielding during upward and downward transitions can help the horse to step underneath himself and round his back as he moves into another gait.
- Turn on the forehands will encourage the horse to step underneath himself and into the outside rein, while simultaneously engaging the core, lifting the back and separating the spinous processes. You must be careful not to let the horse spin on his front feet or push his shoulder too far out of the circle.
- Shoulder turns will lift the spine up higher between the shoulder blades, so that the front end can push upward, giving the hind end space to come underneath the body.
While Kissing Spine can cause a lot of pain, there are things we can do to prevent it. Even if a horse is diagnosed, it is treatable, and many horses make a full recovery. Be sure to check with your vet for advice if you think your horse may have Kissing Spine.
Keep loving your ponies and stay well!!!
Have you read James Rooney DVM’s The Lame Horse? It is sadly out of print but worth buying for his clear explanation of how ‘kissing spines’ comes about. Once the problem develops, it is is a life-long management issue. Prevention is key and drove me to including how to work WITH the functional anatomy of the horse’s back in my horses training series ‘Light in the Saddle’. My insistence led to my publisher dumping my contract because they ‘didn’t like anatomy’ but I went ahead and e-published the books myself in the hopes of educating a few humans and helping a few horses.
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