If your horse is tossing his head or hanging his tongue out while being ridden, going “behind the vertical,” or bearing into the bit, then bone spurs might be the reason. Bone spurs are inflammations of the membrane of fibrous connective tissue that covers the mandible. They usually occur between the corner incisor and second premolar (interdental space) of the lower jaw. The majority of these are caused by bit damage. However, with a simple surgery performed on the farm with the horse under sedation with local anesthesia, bone spurs can be removed and the horse returned to active work.

In his presentation at the American Association of Equine Practitioner’s Convention (AAEP) called, “Surgical Removal of Mandibular Periostitis (Bone Spurs) Caused by Bit Damage,” Thomas Johnson, DVM, a practitioner at Advanced Equine Dentistry in Grass Lake, Mich., discussed the causes and diagnosis of bone spurs, how the surgery is performed, and what is involved during recovery.

Since lower jaw impacted wolf teeth, bone sequestra (separated dead bone), mandibular fracture, foreign body intrusion, and an aberrant tooth bud can also cause the above behaviors, it is best to have a veterinarian examine your horse. Performance horses ridden with a large amount of bit contact are most at risk, said Johnson. This includes dressage horses, gaited horses, Western working horses, Standardbred and Thoroughbred racehorses, gaming horses, and polo ponies. Horses with thin, tall bars instead of thick, round bars are more likely to develop bone spurs. In addition, an inexperienced rider or one with overzealous hands can unknowingly injure the horse’s mouth and cause this problem. He cited work done by Hilary Clayton, BVMS, PhD, a gait analysis specialist at Michigan State University’s Mary Anne McPhail Equine Performance Center, where she showed that bit pressure can range from five to 75 pounds, depending on the rider. W. Robert Cook FRCVS, Ph