The Essential Jaw

Following on from our contemplations on the principles of Osteopathy, it seems natural to begin to consider some of the specific problems and syndromes that are commonly encountered in the performance horse. While focusing largely on the performance horse, the mechanical stresses in sporting dogs are often similar and principles of evaluation and treatment remain the same and may therefore be extrapolated in many cases.

I frequently have the privilege of helping horses who are showing signs of dysfunction in the TMJ – the Temporomandibular Joint. This is a fancy name for one of the most important joints in the performance horses body; the Jaw.

Symptoms that might suggest your horse is suffering from TMJ dysfunction might include localised pain or tenderness, leaning on the bit, resistance to one direction, poll flexion or one-sidedness, dropping a lot of feed or passing whole grains in his manure, ear or poll shyness, head-shaking, unexplained mild to moderate lameness especially “bridle lameness”, or generally being out of character.
Common management factors such as reduced grazing time and increased grain consumption, feeding from a raised feed trough, routine dental work, the use of various kinds of bits and nosebands can initiate or exacerbate dysfunction in this region. Injuries to the poll, pulling back or hitting the head in the stable or horse box are also common events leading to TMJ dysfunction. Conversely, dysfunction in associated regions can result in compensatory TMJ dysfunction as the horse attempts to work around discomfort in these areas.
The TMJ is an amazing joint, functionally it is involved in the simple act of chewing, the horses sense of balance, as well as being structurally linked to the rest of the body, from the upper neck to potentially as far as the pelvis. Because the function of the lower jaw requires so much movement for day to day survival, structurally it has come to be a complex joint allowing side to side movement, lengthways towards and away from the front teeth (retraction and protraction) as well as opening and closing. The structure of the joint itself is enhanced by strong connective tissue, musculature and nerve supply which supports the joint and enables the movement required. This tissue directly links the jaw to the base of the skull, the upper and lower neck and the structures through the upper respiratory and digestive system. Through the base of the skull run important cranial nerves which are responsible for many higher level functions in the head and the respiratory and digestive systems. The musculature from the upper neck functionally links the TMJ to the shoulder through both gross motor muscles and small deep postural muscles. The connective tissue of the TMJ also has slips to the connective tissue surrounding the spinal cord which ultimately ends at the level of the sacrum in the pelvis, functionally linking the jaw and the pelvis. Due to all these anatomical and functional links, the balance between the two sides of the jaw is integral to the correct functioning of all these systems. As such, when there is a loss of free range of movement and balance in the TMJ, the horse can suffer significant amounts of discomfort and ultimately loss of performance.
Osteopathically, the jaw is a satisfying structure to work with. Bringing balance to the TMJ typically triggers a cascade of improvements in many systems. Certainly, as with any other structure in the body, it is not a cure-all, however its effect locally as well as in functionally associated regions is powerful. Following release of the jaw horses will often yawn or shake their head, their expression often changes to a more relaxed and ‘happy’ demeanor. It is not infrequent to see a total relaxation of the whole horse due to the intimate links between the connective tissue of the jaw and the base of the skull and its cranial nerves. Upon walking the horse out, an increased freedom and length of gait is generally noted, due to the relationship of the jaw to the shoulder as well as the pelvic region through the spinal cord connective tissues.
If your horse is showing any of these signs it is well worth having him assessed for possible TMJ and surrounding dysfunction. As discussed, treatment can result in some huge improvements in performance and attitude. If you have experienced the days you wake up sore or with a headache and yet still have to go out and do your days work, you know how grumpy this can make you. Give your horse the benefit of being free of this kind of discomfort and you might find yourself and your horse coming ahead in leaps and bounds.

Author: Our Osteo

Osteopath to every member of the family.

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