CHAPTER 106 Vertebral Facet Joint Syndrome
In horses, as in humans, a complex of inflammatory processes in and around vertebral facet joints can lead to a painful condition known as facet joint syndrome. The initiating incident in this syndrome is damage to the facet joint, primarily to the joint capsule and adjacent connective tissue and sometimes the cartilage or subchondral bone. In horses this primary incident often involves traumatic injury, when the horse slips, falls, flips over, gets cast, or injures itself in some other way.
CLINICAL SIGNS
When lumbar facet joins are involved in facet joint syndrome, the most affected gait is the canter because in canter the dorsoventral flexion of the lumbar part of the vertebral column is most pronounced. Also lateral gaits such as shoulder-in, travers, and half-pass can show alterations when lumbar facet joints are involved because rotation in the lumbosacral region of the column makes an important contribution to these gaits. In racing, dorsoventral flexion of the lumbar segment of the column is a prominent contribution to the propulsion phase of the hind limbs, and loss of performance may be caused by lumbar facet joint syndrome.