20/10/2025
Let's talk about a condition that affects horses (more commonly thoroughbreds) and is not as common as you have been lead to believe.
Overriding spinous processes aka 'kissing spine'
What is it? Anatomically it's where the dorsal spinous processes (DSP's) of the thoracic +/- lumbar spine are touching, causing pain and therefore poor performance.
What signs am I looking for? Bad behaviours such as bucking, resistant to tacking up, bolting and refusing to jump, hindlimb lameness or poor movement in the hindlimbs. Factors such as the horse's conformation, the length and shape of the
thoracolumbar region, and biomechanical stresses related to riding and
performance can influence the development and impact of DSPs.
Now here is the important part - Diagnosis is made during a physical examination and by using diagnostic anesthesia (nerve blocks) NOT ON IMAGING/XRAYS ALONE, as they do not correlate with clinical signs or level of pain. It is also important to consider the angle that the x ray has been taken as it can influence the amount of space present, resulting in over diagnosis.
Ultrasound should be used to assess the articular facets for signs of osteoarthritis and the supraspinous ligament. Referral for Nuclear scintigraphy (bone scan) can be used to highlight that this area is inflamed. Another important aspect of the examination using x rays is to examine the plantar angle (PA) of the hindfeet, because there is a known correlation between negatively rotated hind feet plantar angles and over riding dorsal spinous processes. Any imaging modality used must be followed up with nerve blocks to confirm that this is the source of pain.
Treatment can be multi modal meaning that local infiltration of corticosteroids or the use of mesotherapy +/- shockwave can make the condition manageable. There are several surgical procedures that can be performed transecting the interspinous ligament and there are several bone reducing procedures that can be performed.
Horses with kissing spine require management for pain and tailored exercise warm ups, consideration to the weather when riding, correct saddle and girth fit, maintenance of a healthy weight with diet, and addressing any underlying foot balance issues or hindlimb lameness issues.
So next time your horse has back pain, remember this is not the 'only' cause of back pain and you need a qualified opinion to rule in or out the underlying issue which should start with a lameness examination.
Pictured is a horse that does not have clinical 'kissing spine' but appears to have 'obvious' radiographic abnormalities. Reference Sue Dyson "The Equine Lameness Program"