Turner conducted a large scale study on the incidence of Kissing Spines in 4407 horses presenting to an equine veterinary practice between 2004 and 2011.   

Kissing spines are also known as Overriding dorsal processes. The causes of this condition are complex and not well understood. So the aim of this study was to elucidate the factors associated with Kissing Spines.

Diagnostic procedures included palpation,  Thermography or infra-red imaging and radiography. Kissing Spines were diagnosed if two or more spinal processes were in contact with each other.


The most common reason for referral to the clinic were observable changes in the horse’s behaviour.  These changes were a combination of the following.

  • GROUND BEHAVIOUR. The most commonly reported changes in ground behaviours were sore to touch, girthy and/or brushing hypersensitivity.
  • RIDDEN BEHAVIOUR - The most commonly reported changes in ridden behaviour included intermittent toe dragging, bucking, rearing, head tossing, kicking out and excessive shying, hollow back, hard to get on the bit, stiff in one direction, trouble in gait transitions, changes in head carriage and/or slow to warm up.
  • DISCIPLINE SPECIFIC BEHAVIOURS  – These included clipping fences and rushing.

The next most common reason for referral was lameness.  Including hip and pelvis problems, stifle pain and neurological signs.


The epidemiology of Kissing Spines was as follows.

  • Of the sample of 4407 horses back pain was identified in 310 horses. Of these 310 horses 212 horses (68 percent) were diagnosed with Kissing Spines.
  • The incidence of Kissing Spine was high in pure and cross Thoroughbred horses.
  • Kissing spines were more common in geldings.
  • Overriding spinal processes were more evident in horses between 6 and 10 years of age. Dressage was the most common discipline associated with Kissing Spines.
  • The Kissing Spines were most often observed in the Thoracic vertebrae T45 to T17 and the average number of affected vertebra was 4.3  


 In some, but not all horses, changing the saddle helped to reduce back pain. This suggests that saddles are not the cause of Kissing Spines, but may have an indirect impact by effecting muscle tone, restricting the horse’s movement or causing auxiliary pain.  For example, an ill fitting saddle may cause muscle atrophy which in turn weakens the back and predisposes the horse to developing Kissing Spines.  

Around 40 percent of the horses with Kissing Spines did not have signs of back pain.  This suggests that the condition may predispose a horse to pain but the presence of overriding dorsal spinal processes alone is not always a clinical condition.

The incidence of Kissing Spines is in part related to breed, age, conformation and gender.   For example, studies have reported a higher incidence of Kissing Spines in geldings and lower rates in mares and stallions.  These differences are due to the protective effects of sex hormones on bone metabolism and density.  

Thermography was a reliable screening method for identifying Kissing Spines.  The technique had 99 percent sensitivity and 76 percent specificity.  When compared to x-rays the overall predictive validity of thermography was 91 percent.  By comparison the predictive validity of palpation was 67 percent.

The common finding of Kissing Spines between T14 and T17 is due in part to the change in angulation of the vertebrae in this area. This change is a natural reduction in inter dorsal spinal process space and thus contributes to the increased susceptibility of the area to Kissing Spines.

The hypothesis that riders impact in the saddle contributes to the morphology of Kissing Spines has not yet been proven.  However, anecdotal evidence suggests the high rate of Kissing Spines in dressage horses could be the result of a combination of factors including sitting trot work, *oor saddle fit and excessive upward flexion of the back.  The impact of riders on the formation of Kissing Spines could be better understood by research comparing ridden with driven horses.

In terms of treatment, Shock Wave and Mesotherapy (injections of inflammatory drugs along the spine)  improved the horse’s willingness to work.  However, it was stretching exercises that were the most effective technique for reducing pain and returning the horse to pre-clinical performance levels.


Risk factors associated with a [poorer treatment outcome were   back injury in horses under 5 years of age, higher numbers of affected spinal processes and poor owner compliance with stretching exercises such as working the horse in a long and low outline and over poles.


Veterinary checks of your horse’s back should be performed yearly and in competition horses several times per year.  Taking x-rays of the spine requires specialist equipment , but if this is not available then Thermography or palpation are more accessible alternatives.  Riding your horse in a long and low outline, using trot poles and stretching exercises all help to reduce the risk of developing Kissing Spines by strengthening the horse’s back.


Turner TA. Overriding Spinous Processes (“Kissing Spines'') in Horses: Diagnosis, Treatment, and Outcome in 212 Cases. Proceedings of the 57th Annual Convention of the AAEP; November, 2011, 18-22.

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Accessed 18 July 2018