Kissing spines in horses

 

Horses sometimes have back pain, and being an equine detective with your vet can narrow down the possible reasons why.  One such reason is kissing spines in horses, and there’s a lot to know about it and how to treat it. 

 

Table of Contents

 

Anatomy of the spine

What are kissing spines?

Signs of kissing spine 

Diagnosis

Treatment options

Diet

Prognosis

FAQ

 

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Horse anatomy – the spine

 

To fully understand kissing spines in horses, let’s get into some basic anatomy of the vertebrae – those bones that make up your horse’s spine.

 

• The horse’s vertebrae connect their skull to their tail. The spine is divided into several sections, each containing multiple vertebrae lined up in a row. We hope. Each vertebra has a dorsal (meaning pointing up to the sky) spinous process that varies in length, depending on the vertebrae. Think of the spinous processes as bony projections up from the spine. 

 

• Cervical vertebrae are in your horse’s neck. There are seven cervical vertebrae, numbered one from your horse’s poll area and seven toward their body. Weirdly enough, only the first couple of vertebrae are close to the mane, and the rest swoop steeply downward.

 

In this photo – cervical vertebrae are on the far left, the scapula wing on the left, and spinous processes (withers) are above the ribs.

 

• Then, the thoracic vertebrae of your horse’s back are located under the saddle area. Starting at the wither with thoracic vertebrae number one, your horse will have 18 thoracic vertebrae in total. You sit on these! What you know as the withers are really the tops of the first few spinous processes, giving the neck muscles a place to attach. Sometimes, a horse will have 19 thoracic vertebrae. Because horses.

 

Vertebrae behind the saddle 

 

• The lumbar vertebrae extend from the back of the saddle area and stop before the point of the hindquarters. Depending on the horse, they are numbered one to six, or sometimes just one to five. Again, because horses.

 

• Then, the sacral vertebra heads down towards the top of the tail. The five vertebrae are fused to make up the sacrum. Your horse’s hind legs, major muscles, and connective tissues of the pelvis attach here.

 

• The caudal vertebrae finish things off as they make up your horse’s tail. Here, horses get weird and can have between 15 and 25 caudal vertebrae.

 

• Most affected vertebrae occur in the thoracic region, just below your very own butt sitting in the saddle. The spinous processes are quite tall in this area, several inches or so. Kissing spines can also happen further back in the lumbar region.

 

The pelvis of the horse! Super cool.

 

Major ligaments of horse spine anatomy

 

Soft tissues, like muscles, tendons, and ligaments, all interact with the spine. 

 

• The nuchal ligament is a curious structure, running from the skull to the base of the neck along your horse’s topline. There is a traditional ligament along the very top, but as the neck bones descend, large wings of connective tissue connect the ligament to the cervical spine below. The upper corded structure is called a funicular part and transverses the topline from the skull to the withers. The wing-like structures, the lamellar part, reach down from the funicular part and connect to the vertebrae. This complex, elastic ligament supports their head and neck. 

 

• From the withers to the sacrum, there lies the supraspinous ligament, attaching to each vertebra at the spinous processes along your horse’s back.  The further from the head, the more rigid this becomes. The supraspinous ligament restricts movement of the dorsal spines, keeping the vertebrae in place to support the back.  

 

Major muscles of the horse’s back

 

Muscles can be extensors or flexors. Extensor muscles increase the angle between bones, while flexors decrease the angle between bones. 

 

• In the horse’s back, the extensors go from the head to the pelvis and then, down behind the femur, the upper leg bone.  As these contract, they hollow the back, and the neck is raised.  These extensors are paired, straddling the spine, and the three largest ones in the back are the spinalis thoracic, iliocostalis, and the longissimus dorsi. Fun fact about the longissimus dorsi – it can extend the back, making it hollow, and laterally flex the spine to bend.  

 

• The back flexor muscles serve the best purpose: to keep your horse’s abdomen in place and help them breathe. Additionally, these flexors move the ribs and keep the vertebrae aligned. These core muscles are the transverse abdominal, the rectus abdominae, and the abdominal obliques, of which there are internal and external. These abdominal muscles help your horse lift their belly and hold you in the saddle.  

 

What are kissing spines in horses?

 

• The technical term for kissing spines is overriding dorsal spinous process (OPSD) or spinous process impingement. Loosely translated, the spinal processes of your horse are starting to touch, interfere, or overlap with each other. And yes, they can fuse. 

 

• Healthy vertebrae usually rest about 5mm apart, with soft tissues in between.  

 

• A “normal” horse, whatever that is, has mostly even spaces between the spinous processes that allow the horse’s spine to flex and extend, but kissing spines in horses means these structures are bumping into each other.

 

Horses need to flex and extend their backs.

 

 

How do overriding spinous processes (ODSP) happen?

 

• Researchers really don’t have a clear idea of how this happens. 

 

• It’s fairly safe to say that a genetic component plays a role, as the distance between the spinous processes is determined by your horse’s anatomy, and some horses have less space than others. A horse might also be short-backed or have some other genetic anatomy feature that makes kissing spines more likely.

 

• Traumatic events or injuries are another cause, such as trailer accidents, flipping over, or being cast in a stall.

 

• Could poor saddle fit be a cause? Perhaps! It certainly won’t help a horse with kissing spine. 

 

• Improper training methods and poor muscle development certainly play a role, too. 

 

• It has been noted that horses under the age of 5, Thoroughbreds, dressage horses, warmbloods, and even Quarter horses develop kissing spines. It isn’t too discipline-specific and can generally happen to any horse, regardless of their overall equine health status.

 

This horse clearly had kissing spines.

 

Kissing spines in dressage horses

 

This condition is seen often in dressage horses, but it doesn’t make sense – at first. 

• The entire purpose of dressage is to lift the back so the hind legs can come under, take on more weight, and carry out more advanced movements.

 

• When a horse rounds their back and lifts their belly, the spaces between the spinal processes open up. So, how would kissing the spine happen when the back lifts so much? 

 

• Researchers suspect that many dressage horses have kissing spines because of the sitting trot and how the rider’s weight and movement affect the spine.  

 

• To develop upper-level dressage capabilities, there is a large learning curve and years of strength building. 

 

• It’s also noted that hard-working performance horses of many different disciplines, such as racing and jumping, also develop kissing spines. In these cases, the amount and intensity of the work over time can create change.

 

 

Signs of kissing spine in horses

 

• A horse showing signs of pain can’t email us about it, but we can look for signs of back pain that may indicate kissing spines or some other medical condition related to the back. It should also be noted that some horses have severe problems and no outward signs of distress, while others have minimal damage and many related health problems.  

 

• Some common signs to look for:
  • • Lameness
    • Flinching when grooming along the back
    • Reacting to being saddled
    • Overall poor performance
    • Losing range of motion in the limbs
    • Bucking, balking, resisting anything associated with exercise
    • Trouble in the canter, sometimes not holding leads in the hind end
    • Lack of topline improvement, which is likened to poor posture 

 

• We know that horses can be vague regarding textbook clinical signs! Your horse may appear to have other issues, like ulcers, bad saddle fit, sore muscles, hock or stifle lameness, or arthritis.  

 

The damage is past the withers, which appear mostly normal here.

 

Diagnosis 

 

• Talk to your vet if your horse just doesn’t seem right and is showing signs of back pain. More often than not, a complete lameness exam and physical exam can reveal suspected causes and the severity of the condition. Your vet will often rule out the most common causes of back pain and then move forward.  

 

• Perhaps the next step is to do some imaging and testing. This might be radiographs or nuclear scintigraphy (bone scan) to see how the bones interact. Imaging is quite advanced and can even show individual vertebrae interacting with their neighbors. 

 

• Your vet needs to perform some tests and rule some things out before a diagnosis can be made. This starts with your observations of your horse and your feedback while in the saddle. Your vet will want a complete physical exam, including specific lameness checks, to get a full picture of your horse.

 

•  X-rays are definitive when diagnosing kissing spine, but scans, ultrasounds, and thermography can also help.

 

Kissing spines surgery and other treatments

 

There are many treatment options suitable for kissing spine.

 

• Change saddle fit.  This may include different saddle pads, a new saddle, changing the tree, or riding without a saddle. 

 

• Your vet may suggest physical therapy in the form of specialized exercises to target and build core strength. Your horse might also need to start living in a long and low frame to open up the back and work towards gaining top-line and abdominal strength.

 

• Other options include chiropractic, acupuncture, shockwave therapy, medications, and ultrasound therapy. 

 

• Local corticosteroid injections are anti-inflammatory and directly target the area between the spinous processes. Muscle relaxants and pain drugs without steroids (NSAIDs) can be given orally.

 

Types of surgery 

 

• If surgery is recommended, there are a few options here as well. Surgeons can perform an interspinous ligament desmotomy surgery (ISLD), which cuts the ligaments that connect the spinous processes causing the problems. Your horse can also have their spinous processes shaved down or partially removed to create more space. Both of these are under general anesthesia. Surgical treatment may be the best option if other routes are not as successful in relieving pain. 

 

• Of course, your vet’s treatment plan should address the radiographic changes and the surrounding muscle structures.  The rehabilitation of horses with spine problems is holistic, treating the whole horse. 

 

 

From the withers looking towards the tail. Notice the giant scapula!

 

Your horse’s diet

 

• The most important thing about feeding a horse with a kissing spine is allowing them to eat naturally and comfortably. Use hay play nets on ground level so their topline isn’t compromised by eating from a hanging net. 

 

• The goal of any equine diet is to balance the daily nutritional needs of forage, vitamins, minerals, and fats like Omega-3 fatty acids. Then, you can consider how the diet impacts medical issues and diseases.  

 

• We want the diet to be anti-inflammatory, which means lower in sugars and starches. Aim for non-structural carbohydrate (NSC) values of 10% or less in forages and feeds. You may need to switch to grass hay and feeds with lower NSC values. Don’t rely on the bag stating “low-sugar.” It would help if you had the exact percentage. 

 

• Omega-3 fatty acids are anti-inflammatory but are vastly outnumbered by the Omega-6’s in a horse’s typical nutrition plan. The goal is to create more balance by adding Omega-3s in flax, chia seeds, or fish oils. Corn oil is not it, despite generations of horse owners swearing by it. There are too many Omega-6s in corn oil. 

 

• Joint supplements may also help your horse feel better. MSM is an affordable and proven joint supplement that may help the back.  

 

• An equine nutritionist is the best person to help create a diet for your horse.  

 

Saddle fit isn’t a one-time deal – it needs to happen regularly, like every six months or so. Read more about saddle fit here.

 

 

What does this mean for your horse?

 

• Well, first, don’t get scared and think that because they crow-hopped they need surgery for kissing spine. They might just be a bit of a silly goose.

 

• As with all things horse, be the detective and start to memorize your horse’s behaviors and how they react to grooming. Go one step further and notice how they react to being touched and gently squashed everywhere.

 

• Kissing spines is another reason to have a great relationship with your saddle fitter and find someone well-versed in your favorite discipline to help you ride and train your horse.

 

• I’m all about being able to ride your horse without someone in your ear all the time, but it helps to have eyes on the ground to make sure your horse is lifting their back, and their spine stays supple both side to side and up and down.

 

• Involve your veterinarian and keep good notes on your horse’s behavior and training!

 

• You will likely be able to perform many medical treatments at the barn, such as therapeutic massage, hot and cold treatments, liniments, and other medical therapies that support your horse’s daily comfort.  

 

Supplemental ice or heat may help your horse, and so can therapeutic blankets.

 

Can kissing spines be prevented in horses?

 

There is no way to prevent kissing spines in horses, but lifestyle management can reduce the risk.  This includes saddle fittings, proper exercise to strengthen the back, and watching your horse’s weight and overall comfort. A balanced diet is also helpful.

 

Are certain breeds of horses more prone to developing kissing spines?

 

Thoroughbred horses are often more prone to developing kissing spines due to their conformation. Their taller withers and relatively short backs can contribute to the condition, but any breed can be affected. Regular veterinary checks and appropriate training methods can help manage this issue in horses.

 

What is the prognosis for horses diagnosed with kissing spines, and can they return to full work after treatment?

 

Proper treatment, including rest, physiotherapy, and, in some cases, surgery, can give horses a good prognosis. With appropriate care and management, many horses can return to full work after treatment.

 

 

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