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A Bit More on Biomechanics

Updated: Feb 21, 2020

A somewhat brief overview of how what goes on with our horse’s mouth and head directly effects the entire function of the body!

One of the biggest reasons that I find it so important to take the whole horse into consideration from a training aspect is because the whole horse is connected in so many ways, top to bottom, front to back! In our last Immersion Clinic, we went over the anatomy of the mouth and why dental work is so important for our horses, regardless if they are ridden with or without the bit. Having a general understanding of the importance of function is crucial!!

First and foremost, our horses teeth continuously erupt and wear, and without regular care can develop painful edges, hooks and “waves” in the teeth, making relaxation and movement of the jaw very difficult. Of Course movement of the jaw is important when it comes to a horse eating, if they do not have full range of motion, consumption of hay and grain becomes challenging and painful, often creating tension in muscles that need to brace in order for them to have some sort of function. With a horse in work, either ridden work or ground work, this movement and relaxation of the jaw is crucial, especially when we are looking to educate a horse in the realm of Classical Dressage, but in reality, every equine sport!

The mouth of a horse is much more complex than simply being a portal to which copious amounts of food disappear! We have of course the teeth, incisors, molars, canines and sometimes wolf teeth. Then there are the lips which consist of thick muscular tissue, ideal for grabbing and sifting through forage. The palate, which consists of soft and delicate tissue, which covers the thin bone of the roof of the mouth. The bars of the mouth that are part of the lower jaw, covered by thin and delicate gum tissue. The tongue, which is the strongest muscle in the body of the horse (yes!! I was a bit shocked myself as there are some very impressive muscles in the equine anatomy) and is also much longer that you would suspect. Continuing from there we have the hyoid apparatus, a delicate boney system that hangs on the inside of the horses jaw, and is connected to the tongue and trachea. Then there is the temporo mandibular joint which connects the jaw to the head and the complex muscular system around this joint, and the top of the skull which enable the horse to move the jaw and chew effectively. These systems are all connected to the rest of the body via muscular, ligament and fascial systems!

The above image generally illustrates the above stated structures. Of course not everything is shown here, there are many small muscles in the head connecting the hyoid, jaw and poll that are not shown, but this gives the viewer a good idea as to just how much is connected! The tongue is further connected to the sternohyoid muscle group which connects to the chest and effects movement of the front limbs. Then we have the nucal ligament and muscle groups around the poll, which are connected via fascia and muscles to the hind end of the horse, effecting the movement of the hind limbs. In short, the entire horse and how it functions is connected to the head and mouth, so optimal function of the mouth is crucial to function of the entire body!

The image to the right illustrates the complex muscular, fascial and ligament systems of the neck and into the head. Something to note is that these structures are the main connection of the head to the neck, as the C1 vertabrae is the only supportive boney structure that delicately connects the head to the neck. The soft tissue structures play a crucial role in the connection and stability of the head!

How can poor, irregular or no dental work restrict the movement of the jaw and mouth? I briefly mentioned the horse not being able to eat out of discomfort and holding tension, but what exactly causes this? If sharp points develop on the outside of the molar, these points constantly threaten to injure the soft and thick cheek tissue either by constant rubbing, causing ulcers to develop, or by not allowing the horse to articulate fully when they chew because if they do they will end up biting and cutting their cheek. Horses do not chew as we do, they grind their food while we chew so their jaw moves in a more circular and side to side motion instead of up and down which is why their teeth get worn in certain patterns. On top of these harsh points developing, hooks which are basically massive points on the back molars may develop. If hooks become large enough, they could restrict the ability of the jaw to slide forward when a horse puts its head down to graze, or softens while being worked, causing the jaw to be "locked", which in turn locks all of the connective tissue in the head, neck and limbs. With these two issues alone, points and hooks, can seriously restrict the side to side motion as well as forward and back. To test out your horses jaw movement, you can gently hold the top of their head with one hand, and jaw with the other, and with a bit of muscle, wiggle the jaw from side to side and you can feel if it moves more one way than another, not at all or if there are "sticky" spots. if all feels fairly smooth and you can hear the light grinding of the teeth, then your horse may be in good shape, but it is always best to have a professional check when requested.

So hypothetically, you have had your horse's teeth done on the regular and they have a well functioning mouth, but you feel a bit perplexed, your horse still seems very stuck through their body and is heavy on your hands. You have tried a few different bits but it seems to be the same regardless. You and your horse made some progress, but now it seems like you have to work harder and harder to achieve the same thing and moving forward just seems like it's not going to happen. What could be the issue? Like everything else, it could be a wide array of issues, but we are going to focus on what may pertain to the head and mouth for today. But each horse and rider is different so they cannot all be treated and diagnosed in the same way. First and foremost we cannot combat heaviness with heaviness, it may seem counter intuitive to us humans, but if your horse is pulling, leaning, yanking, do not do it back to try and get to neutral! This will only further cause more brace etc from the horse because now they expect you to do the same. The bit should be seen more as guided support, not something that is relied upon by both horse and rider to keep everything together. In this case, awareness and fluidity may greatly help the situation diffuse. But if you try and do your best to not get in a tug of war with your horse, then there may be other issues that need to be addressed. Check your noseband if you ride with one, the general rule is that you should be able to comfortably fit two fingers between the bridge of the horse's nose and the noseband. If you have resorted to tightening the noseband or flash because your horse has been too fussy in the mouth you figuratively shot yourself in the foot! Mechanichally restricting movement doesn't mean the issue is fixed, it means that you are forcing it to not happen, causing much more tension than what you started with. A moving and soft jaw allows for the connective muscles in the head and neck to stay soft and supple through movement. Think of a shut jaw as shutting the door on any chance your horse has of "correct" forward movement. On top of tension, a tight noseband also prevents the horse from being able to swallow regularly, move it's tongue and pushes the tissue of the cheek into the molars. Overall dicomfort and lack of mobility pretty much invites the horse to brace against the rider and more and more needs to be done to combat the issue until you have a horse who is moving in a false frame through tension and forced forward movement. This forced frame often shows a horse short and tense in the neck with a compressed throat latch, that now restricts breathing and compresses the muscles connected to the hyoid and tongue adding more fuel to the fire. Regarding my last blog speaking of the importance of function of the thoracic sling, with restriction of the mouth and connective muscles of the hyoid and neck that tie into the chest, they in turn restrict the function of the thoracic sling mechanism, again making it vastly difficult or impossible for the horse to lift when that is what you are trying to accomplish! It becomes a vicious cycle until in theory you and your horse get to a point where things seem impossible and nothing is enjoyable. Too often it is easy to get to this point without a supportive team of professionals guiding you through the process helping and educating you when it may seem like there is a fork in the road.

Now if your horse is being "mouthy" how is it determined if it is healthy/regular activity, or due to stress and or discomfort? If teeth have been checked and the noseband is properly adjusted and fitted, it is time to examine type of bit and methods of achieving contact. The wonderful thing about being a horse person in 2020 is that there is so much out there in terms of bits, information and research! But this can all be a bit overwhelming as there is just so much to choose from, how on earth do you know if you are choosing the right thing, and how do you not spend a fortune on bits in the process of trial and error?! I have a few suggestions that may make it all a bit easier and less consuming of your paycheck. One great resource is your dentist, while they are out working on your horse ask them about your horses mouth! Does your horse have a low palate, wide mouth, beefy tongue, a substantial bar purchase, thick cheeks and lips? All of this information will be helpful in determining what bit may be most comfortable for your horse and narrow down your search. Another helpful individual is a savvy and intuitive trainer who is able to feel and understand what your horse may be defaulting to with the current bit that they have. Are they not taking contact, rooting, leaning on your hands, seemingly dull and unresponsive, head high and almost afraid of the bit making contact with their mouth, excessive chewing, gaping mouth etc. What may possibly be a training issue and what may be a bit issue and getting this information will further narrow your search. Of course if you are looking to show in a specific discipline then you have to remain within the parameters of what is legal for each sport, which again will narrow everything down even more! Before spending a dollar on a new potential bit, you will already have an educated list of what may work for your horse, now the rest is up to your equine partner and what they prefer. Your horse will "tell" you what bit is most comfortable to them and so ultimately they are the best judge! But again, before purchasing anything just do a bit more research and see if there are any consignment shops close to you. I am lucky to live in a wonderful southern town where we have a plethora of tack stores and consignment shops so it is fairly easy to look for something used first. There is no sense in buying something brand new if you don't know if you are going to keep it! If you are out of luck and there are no consignment or used tack shops, don't be shy and ask around your local equestrian community and see if anyone may possibly have the bit(s) you are looking for and see if you can just test them out on your horse. The worst thing they can say is no, and if they say yes can be super helpful to your search. Once again, if where you live with your horse doesn't have much of an equine community and you are a bit out in the middle of nowhere, then you can resort to buying a used bit online. Believe it or not, Facebook is a great place to find lots of used gear, but beware, someone may sell you a bit that may not be in the condition they claim and the last thing you want to put in your horses mouth is a compromised bit! These are great tips, but how can you tell if the bit works for your horse? What is it that you should be looking for? Well, it depends on the horse and depends on what their reactions were before and remember each horse is an individual so these reactions will vary from horse to horse. But a general answer to this question of what to look for is: softening of the horse's facial expression, soft lips no longer pursed, relaxed jaw and surrounding muscles, blowing out, a sigh, yawning, willingness to "take" your hand, being less fussy in the mouth, softer in the mouth, healthy salivation, easier ability to obtain flexion, a downward bobbing head and neck opposed to an upward bobbing head, ability to swing the forelimbs further etc. The first bit you try may not be the right one, it may not be the second or third either, but listen to your horse and how they respond to each one. Most importantly, if the issue is a training issue, please be wary of anyone telling you that a "harsher" bit is needed to achieve what it is that you are looking for, this is like putting a band aid on a broken bone and will only lead to further issues down the road for both you and your horse!

My client Rachel and her lovely horse Patriot are a great example of how a change of bit, training and feel of the rider has made some lovely changes in the horse. Both Rachel and Patriot improved greatly to allow for freedom of movement through the whole horse and how it translates into lovely hind end engagement and engagement of the thoracic sling. In this stage of their training, allowing for an open neck helped Patriot soften the connective muscles in his jaw, which in turn allowed for suppleness front to back.

Luckily these issues can be addressed through the help of a professional who understands the importance of fluidity and function of equine anatomy and who can ensure that you are continuously heading in the right direction, building your horse up with the correct foundation, as well as recommend having other professionals come out if it seems needed. Too often horses are seen as these large animals that need to be subdued through mechanical manipulation and strength. This is so far from the truth! Horses are sensitive creatures and with a full understanding of how they work, we can cater to their sensitivity and be much more effective in what we want to accomplish with our four legged partners.

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