"Kissing spine" is the colloquial name for an equine condition known to vets as over-riding of the dorsal spinal processes. This painful condition is caused by sections of the individual vertebrae in a horse’s back touching each other -- the origin of the name “kissing spine.” Horses with shorter backs are more prone to the condition, according to Dr Sue Dyson, a Fellow of the Royal College of Veterinary Surgeons, although it can also appear after a fall or other traumatic incident. The main symptom your horse is likely to experience is back pain.
You may notice that your horse is in pain while tacking up. He may be reluctant to have the saddle placed on his back and may rear up when you attempt to fit it. Poorly-fitted saddles and tack can put pressure on your horse’s spine and increase the likelihood of developing kissing spine, so ensure you’re using the correct-sized kit for your animal.
If your horse begins to rear and buck while you’re riding, it may be a sign that he is experiencing back pain, a symptom of kissing spine. You may also notice a deterioration in your horse’s performance, such as dipping his back when first mounted, rushing fences, struggling with combination fences or jumping flatter than previously. Horses experiencing back pain also tend to have a reduced stride length.
More clues lie in a close examination of how your horse reacts when you stimulate his back. For example, stroke his back muscles firmly and you may notice that they are tense as a result of muscle spasms set off by the touching vertebrae. If you encourage his spine to move from side to side, back pain may lead him to bite or hold his spine stiffly. The key to recognising these signs is to spend time with your horse and get to know his normal movements.
If you suspect that your horse is suffering from kissing spine, contact a vet. Although there is no single test for kissing spine, X-Ray imaging can be helpful in diagnosing the condition because the images can clearly show the vertebrae touching. Another common method vets use in identifying kissing spine as the cause of back pain is to inject local anaesthetic into the area around the affected vertebrae.