Temporomandibular Joint Function

It must first be stated that there has been minimal scientific investigation into TMJ of the horse. Much of the information available is from comparisons with human TMJ issues and a theoretical biomechanical model. Field work with horses, their teeth and their TM joints over the past 15 years also helps to provide clues as to TMJ function and the related issues of bits and performance. This is an area that could provide many answers to neck, back, gait, and psychological issues for the horse. All of these obviously affect the performance of the horse. Equine TMJ issues are unique because we use their mouth and jaw as a communication point. If the TMJ is dysfunctional or painful and the bit is moved to the left or right then the jaw receives lateral pressure to move in that direction. Painful reactions to the bit in the TMJ may be responsible for the horse resisting directional cues. The hesitation involved can be the difference between a first place finish and a less desirable outcome. The term "collection" is found frequently in the horse industry and is used to describe a very specific posture in the horse. Proper posture is strongly and uniquely related to the TM joint in both humans and horses. Substantial evidence and understanding of this posture indicates that it is primary to many of the movements that are actively sought by equine competitors. The ease with which a horse can be collected may rely heavily on correct TM joint function.

The effect of the heat applied with a TMJ hood is to reduce inflammation in the connective tissues surrounding the joint. This is the main compelling feature of the treatment protocol. Reduction of pain will help the horse to increase the lateral movement of the jaw, in other words increasing the range of motion of the joint. This increased range of movement then improves the overall function to the joint and its connective tissue as well as the general function of the masticatory (chewing) machinery of the horse. As the horse is better able to relax in its jaw and neck, a direct translation in improved performance is obvious. Better head sets and easier flexion at the poll will improve the gait and stance of the horse.

Therapeutic effect of the TMJ hood is again enhanced by competent dental work that goes beyond regular rasping of sharp points and is designed to promote proper mouth function.