Neck pain in horses is not commonly diagnosed, but it may be more common than we realize in older performance horses.  Pain and stiffness in the neck can certainly be a cause of poor performance, and a change in gait may be difficult to recognize in subtle cases.  Many horses may simply be a little off and it is difficult to pinpoint the neck as the cause of the problem.  Sometimes horses will have a forelimb lameness that is due to nerve root pain starting in the neck while some horses will be resistant to turn or will even wobble in the rear legs. 

Dr. Carla Pasteur indicated in the Clinician that neck pain may be due to joint pathology, tendon or ligament strain, myofascial injury, or nerve inflammation.  Eliminating pain does not always solve the problem as there is usually a lack of muscle development, muscle atrophy, and abnormal muscle tension involved.  Resistance to lateral bending of the neck is considered a training issue by many folks, but if the horse is in pain or lacks neuromuscular control, training is not going to be effective.  A normal horse should be able to bring the head around to the level of the elbow at a neutral height without rotating the head and neck.  Horses that prematurely rotate the neck generally are found to have neck pain.  Arthritis in the cervical factet joints is common and can lead to nerve dysfunction, such as front leg lameness as well as neck pain and instability. 

Treatment involves pain medication and sometimes injecting the joints with anti-inflammatories.  Some rehabilitation techniques have been successful in strengthening the neck muscles, which aids in stabilizing the vertebral bodies, decreasing pain, and increasing lateral bend.