New research insights on equine spinal conditions help veterinarians extend horses’ soundness and longevity

Stretching from skull to tail, the horse’s vertebral column contains 51 to 57 vertebrae that shape movement, balance, and performance. Each of the spine’s cervical, thoracic, lumbar, sacral, and  coccygeal regions can develop its own specifi c disease processes involving bones, ligaments, muscles, cartilage, and/or nerves, creating a wide array of clinical signs that can make diagnoses challenging, says Sue Dyson, MA, VetMB, PhD, DEO, former head of clinical orthopedics at the Animal Health Trust Centre for Equine Studies, in Newmarket, England.

“We’ve got this huge spectrum of problems, and different areas that can get damaged, which result in a wide variety of clinical signs related to each—obviously with different diagnostic and management challenges,” she says.

Fortunately, researchers continue to uncover better ways to diagnose, treat, and prevent such problems, says Kevin Haussler, DVM, DC, PhD, Dipl. ACVSMR, associate professor at Lincoln Memorial University, in Harrogate, Tennessee. “There has been a lot of progress in spinal-related issues lately, so it’s an exciting time,” he says.

Neck and Spine Problems: An Overview

Spinal issues in horses include bony changes—such as remodeling (changes in size and shape), arthritis, misalignment, and fractures—and soft tissue injuries affecting muscles and ligaments, Dyson says. Nerve compression can also occur, causing lameness, weakness, stumbling, or difficulty bearing weight.

Conditions arise from damage to the spinal cord, and the signs vary depending on the location of that damage. In the cervical region, for example, horses might develop intervertebral disc disease or damage the nuchal ligament—which anchors at the back of the skull, then runs down the neck and attaches along the bones of the neck and into the withers—and its bursae, which are fluid-filled cushions that sit between the ligament and the bones it rubs against. The withers serve as a key transition point between the neck and back and can suffer fractures from trauma.

Further back, in the thoracic and lumbar regions, two or more spinous processes can touch or override one another, forming impinging dorsal spinous processes (IDSPs), while arthritis might affect the articular process joints. Additionally, spondylosis—new bone on the underside of the bones—can occur in the vertebral bodies. The lumbosacral area experiences major spinal flexion, mediated by large muscles under the spine, putting it at heightened injury risk. The junction between the spine and the ilial wings, called the sacroiliac joints, “presents another completely different set of problems,” Dyson says.

As for tails, our sources say they can incur fractures, soft tissue injuries, and neurologic problems. But their pathologies (disease or damage) remain largely understudied.

The Latest in Imaging

Radiographs (X rays) still serve as a great starting point for viewing spinal bones in 2D, Dyson says. But in the past decade computed tomography (CT) has advanced to provide 3D images of the entire neck and upper thoracic spine