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Essential Knowledge for Equestrians: The Intriguing Anatomy of a Horse's Head

Updated: Jun 5

When I first heard world renowned Equine Veterinarian and Dental Vet Specialist Dr. Chris Pearce from the Equine Dental Clinic present at the Horses Inside Out Conference in February 2023, I came away with mixed feelings. What I had just heard and learnt from Chris was absolutely fascinating and exciting for horses and the future of Equine Dentistry whilst at the same time making me feel uneasy about some of the dentistry practices, dental complaints and bitting injuries that horses have had to and are still having to in some cases endure.

For me Chris had opened up a dialogue that I felt really needed to be explored further, and I was really pleased to learn about the campaign with the BHS - No Pain, Check Again which was being promoted at Your Horse Live this year and can be viewed by anyone online.

When I heard that Gillian Higgins and Chris would be teaming up for a whole day live online seminar all about the horse’s head, I couldn’t wait to be there so that I could learn more, and make sure that as an Equine Therapist and horse owner I am as well informed as I can be on this subject, in order for me to be able to advise my clients and make recommendations.

I have to say this day was a complete marathon, absolutely jam packed with information and it’s hard to know where to start when thinking of condensing some of what I learnt and points I found most useful. So I am going to do my best to give you a taste of what the day entailed and hopefully this will whet your appetite and encourage you to purchase the online recording of the seminar for yourself so that you can learn more about what is going on inside your horse’s head!

If you have noticed poor performance in your horse and are struggling to find the route cause, this seminar might give you some ideas of what else you may be able to consider as the issue.….?

The day started with GIllian explaining some of the anatomical connections of the head and how the head of the horse should not be thought of as a separate structure of it’s own, as of course it is connected to the rest of the horse’s body. Often in anatomy we think of how the muscles work together in chains and Gillian often talks in her demonstrations about the Flexor Chain of muscles and the Extensor Chain of muscles. You can read about this in my previous blog or in some of GIllian’s books.

What is interesting to consider is how there are muscles of the head that are part of these chains including the Masseter muscles in the Flexor Chain, and the Temporalis muscles in the Extensor Chain.

But as the Masseter and Temporalis muscles meet eat other under the Zygomatic Arch on the horse’s skull, are they in fact one chain? And where does that chain begin or end?

I think it’s interesting to think about these connections when making considerations about whether issues in the horse’s head affect other areas of the body (or not?).

Chris then went on to discuss Dental Disease as a possible cause for poor performance.

He raised a very interesting point about the Ridden Horse Ethogram by Dr Sue Dyson, which she presented at the Horses Inside Out Conference and you can read more about here.

The ethogram is designed to help recognise horses with musculoskeletal pain, but we must look at the whole horse, and other areas such as oral/dental or visceral issues could be also causing some of these same behaviours.

I thought a very interesting point he raised was the pre purchase exam x-rays that are commonly taken, it is very rare that the head is actually included.

As an owner or professional, would you recognise if your horse was displaying a ‘pain face’

Anatomy of the horse's head in detail: hyoid, tmj, social licence, dentistry, science, standards, equine pain face

Chris and his clinic conducted their own unpublished study with a large number of clients with horses that had been diagnosed with dental issues and 62% of the owners had reported their horse showing no noticeable symptoms prior to examination.

This is why he stresses that regular examination is so important. Horses by nature are designed to hide pain and can become very efficient at eating around the pain and not outwardly showing signs.

Chris explained how symptoms can often be minor, or mistaken for something else, some he shared with us were:

  • biting

  • not drinking cold water

  • pausing when eating

  • ‘stiff’ to ride on one rein

  • head shy

  • grumpy with other herd members

  • reluctance to be brushed/tacked up

  • Self mutilation

He shared with us also many case studies with images and videos of what can be going on inside a horse’s mouth, including shear mouth, ulcers, fractured teeth, root disease, sinus infections, facial swellings, abscesses, EORTH, diastema & caries.

Horses in the wild would often die young from dental disease, with a life expectancy of around only 10-12 years.

As custodians of horses we owe it to them to make sure they do not have to suffer from these issues. It really is eye opening to see some of these things that are often easily missed.

So what should we as owners be doing? Having an annual rasp from our local Equine Dentist, is this enough?

Chris shared with us what he believes should be the hierarchy of a professional dental team. And that the Gold Standard in dental care should include a sedated orascope at least every couple of years to have a thorough check for any issues as well as regular check ups with a BAEDT registered Equine Dental Technician. He could not stress enough checking that your technician is on this register, you can check that here.

Anatomy of the horse's head in detail: hyoid, tmj, social licence, dentistry, science, standards

Next Gillian discussed the anatomy of the horse’s head related to bridle fit and design.

I liked the way she demonstrated the pressure points on the horse’s head from the noseband.

It’s easy to forget that the horse’s ‘nose’ is not actually a circular shape like the nose band often is, so there will always be pressure points in certain places. What is useful to consider is how the pressure that is there will certainly increase the tighter the noseband is. And discomfort from the noseband is likely to increase if there is poor dental health.

Anatomy of the horse's head in detail: hyoid, tmj, social licence, dentistry, science, standards, gillian higgins

Gillian then discussed bridle head piece anatomy, which bony landmarks we should be trying to avoid when fitting a head piece and the importance of taking into consideration the conformation of each individual horse e.g how much space they have between the Auricular cartilage of the ear and the wing of the Atlas to fit the head piece..? You can learn how to feel for these points in the seminar.

Next Chris discussed bitting injuries and how to avoid them. I really liked the history of bits that he shared from an old loriner’s book (a loriner is a bit maker) You can see from the image that even in these early days it was known that the bit should be used as a tool of communication and should in no way be injuring the horse.

Anatomy of the horse's head in detail: hyoid, tmj, social licence, dentistry, science, standards, bits, bridles, dr chris pearce

And yet it seems from the images and experiences shared by Chris, bitting injuries are sadly very common.

They include injuries to the:

  • Lip commisures (which can be cuts or scarring)

  • Soft palate

  • Tongue

  • Pouchy Flesh (overlying the mandibular bar)

  • Cheek Mucosa (ulceration or lesions)

  • the bone of the Mandibular Bar

  • the Teeth

And causes can include:

  • Bit mouthpiece too large (causing movement of the bit in the mouth which can create lesions)

  • Loose Ring bit too small

  • Losenge too wide

  • Straight bar bits (put more pressure on the bars of the mouth)

  • Noseband too tight

  • Horse chewing the bit

  • Too much leverage on a bit

  • Rider/Horse disconnect

Chris followed on by sharing some published research into bitting injuries in horses which was interesting and eye opening as well as offering advice on how to use this information to help us avoid bitting injuries in our own horses.

During the Q&A I took the opportunity to ask Chris for his advice on anything we can do as horse owners between our horse’s regular dental check ups to help them maintain good dentition.

His advice was to provide the following things for our horses:

  • Plenty of forage

  • Regular Turnout

  • Good quality hay (avoid stalky or late cut hay where possible as this can get stuck between teeth, cause gaps and food pocketing, especially in older horses)

  • Minimise stable time

  • Minimise concentrates (feed)

The next part of the day was a virtual tour around Chris’ clinic - The Equine Dental Clinic. If you haven’t already seen this I would highly recommend taking a look, it has been shared to the Horses Inside Out Facebook page, as well as being part of this seminar if you purchase this.

Chris hopes that visits to clinics like his, or at least Orascopic examination in a clinical setting, will soon become the ‘New Normal’ in the Equine world.

For those of you that are not familiar with an Orascope, it is a tiny probe with a camera on the end that allows the dental specialist to look inside the horse’s mouth with the image shown on a large TV screen.

A light sedation is mandatory for this procedure but allows for such a thorough examination and stress free treatment for the horse. Usually only taking a very short time.

Anatomy of the horse's head in detail: hyoid, tmj, social licence, dentistry, science, standards, dr chris pearce, routine maintenance dentistry, equine dental clinic

This type of treatment is more closely modelled on human dentistry which is a more productive as opposed to reactive approach. Small things can be noticed and treated before they become an issue for the horse and bigger problems can then hopefully be avoided.

Chris believes that as the human knowledge of equine anatomy has developed along with the understanding of dental pain, use of medical technology and understanding of pathology we can now offer our horses a higher level of care and also ensure that we can do enough without doing too much.

Some of the examples Chris was able to share with us of where unskilled work has been performed out ‘in the field’ as well as images and examples of where too much work has been done on a horse’s mouth were really eye opening and highlighted the importance of having a registered technician that at a minimum uses a mirror to check inside the horse’s mouth if not an orascope.

The results from blind rasping, over floating, bit seating, aggressive incisor reductions, teeth cutting and also simply poor examinations are plainly scary to see.

For the final part of our day we were treated to a further 2 talks from Gillian and then Chris with the topic being the TMJ (temporomandibular joint) and the Hyoid apparatus. Gillian shared with us some Anatomy & Biomechanics of the areas whilst Chris talked about some of the scientific reviews of problems in these areas.

This is an area that is often well discussed when it comes to issues of poor performance in horses related to the head. Gillian presented some fabulous images and videos explaining how to find these areas in your horse, what their function is as how they may be compromised.

Anatomy of the horse's head in detail: hyoid, tmj, social licence, dentistry, science, standards, gillian higgins, temporomandibular joint, equine

Chris then went on to share the published research and why science, scientific papers & testing are so important to help us make informed decisions about what may be going on with our horses and how these areas have been proven to be compromised and their proven (not anecdotal) effects on the wider body of the horse.

I found this very though provoking, I believe there is always going to be people with anecdotal evidence to support claims of things that may not have yet been scientifically proven, but I do agree that peer reviewed research with a control group is also very important. I found the entire day thought provoking though, there was so much to take in, and one of the key messages as always is to have a whole horse approach when it comes to horsemanship and horse care.

And how many of us really know what is going on inside our horse’s mouths? Since the conference in February 2023 I booked my own horse in for an orascope examination and all I can say is I am glad I did!

In the words of Dr. Chris Pearce - ‘No Pain? Check again!’

Watch the on-demand seminar here:

Listen to Chris's presentation at the conference in February:


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