09/02/2024
It’s all in your head… or your horse’s head!
Fitting a Bridle Properly - Part 1
I’m going to take a slight detour and diverge from discussing saddle fit to discussing bridle fit. Even though you may know that of course, your bridle has to fit your horse properly, you may be surprised to hear of the impact a poorly fitting bridle may have on your horse. Bridle fit can be considered just as important as saddle fit to maintain your horse’s comfort and optimum performance.
No other part of the anatomy has as many sensitive areas as the head. Recent design changes in bridles to become more ‘anatomically friendly’ are crucial in ensuring your horse is comfortable with his headgear. There are many nerves in the horse’s head. Some of them originate in exactly those areas where the noseband or flash lies.
If a bridle is too tight, all sorts of behavioural issues can arise, including tossing the head, lack of chewing, and lack of engagement with an unwillingness to move. These reactions warrant a closer look to what’s under the skin of the horse’s head. The gross anatomy of the head is easily recognizable in a horse – there is only a thin layer of skin covering the skull, while veins and muscles are only minimally visible. What you don’t see are the multitudes of nerves, and the delicate connective tissue at the various junctions of bone – all of which make the head extremely sensitive to pressure and pain.
This connective tissue between the 29 individual bones of the skull, plus a jaw which allows a side-to-side movement of the teeth during mastication, are responsible for movement of the head.
There are numerous nerves originating at the base of the skull, spreading upwards over the skull – and often present exactly where the various pieces of the bridle would lie. Too much pressure caused by the bridle can also cause referred pain elsewhere; muscles can cramp up and engagement will disappear. Fascia (connective tissue) runs through the entire body. A poorly fitting bridle can even cause problems all the way down to the hocks – impacting the flexibility and range of motion. Although there are unfortunately only a few studies documented concerning how a poorly fitting bridle impacts a horse, there is anecdotal evidence of this, and horses do move better in a bridle that fits. The most severe problems arise in the neck/base of the skull if the bridle fits badly (where the headpiece lies), but a noseband or flash that is buckled too tightly will also cause problems here.
The Neck
Sensitive bursa are found between the nuchal ligament and the first two cervical vertebrae. Bursa are little sacs filled with fluid with the job of preventing the ligament from rubbing on the vertebrae and getting damaged. They cannot withstand a lot of pressure, and will react to a poorly fitting or too-tightly-buckled bridle by increasing fluid production and swelling. They become obviously swollen – for dressage horses this is seen mainly at the atlas (first) vertebra, and in jumping horses mainly at the 2nd cervical vertebra.
These affected bursa are not only visually obvious, but may cause the horse to ignore the aids, toss its heads, or refuse to go on the bit. When it really hurts, the horse may ‘invert’ its neck in an attempt to escape the pain. The muscles of the topline may begin to atrophy, and the horse develops a ‘ewe’ neck. Even well-intentioned padding of the headpiece may actually be counter-productive – instead of helping, padding can even increase the pressure and cause skin folds – which may lead to further concentrated pressure points. (again – it’s trial and error on your own horse to see the reaction to more padding). There is no universal formula for all horses as to ‘how much is too much’ when it comes to the ability to withstand pressure at the headpiece. A sensible rider will listen to her horse and see what works for her (while recognizing that these issues may not necessarily be actually due to a poorly fitting bridle, but could also arise from dentition problems or even simple rider error!)
The bridle should be fitted to allow a hand to slip under easily at the headpiece. There should be two fingers room between the cavesson/noseband and the nose. Bridles should be considered as a DIY craft project – with potentially differently sized noseband, headpiece, and cheekpieces to accommodate the individual horse.
A noseband that is too tight can also impact the horse’s neck and the ability to engage. For full comfort and relaxed movement, a horse’s bridle should still allow the horse to chew freely. Chewing movement means the jaw needs to be able to move side to side freely. If the horse tries to chew with a bridle that is too tight, the resistance will cause cramping of the jaw muscles and pressure in the neck – and this muscle ‘bracing’ will impact the horse’s entire musculature and ability to engage. Some horses are in such pain around their heads that riders may have misdiagnosed them as being ‘head shy’. This can be avoided by properly fitting bridles.
If there is too much pressure at the base of the skull from the headpiece, irritation results. Experiments have shown that during a canter while on the bit, the pressure is doubled here. Since the nerve here is also connected to the skin at the ears, the horse will show reluctance to have his ears touched when there is too much pressure from the bridle. This nerve also connects to the tongue musculature, possibly leading to further problems in the forelegs, since the muscles here are also connected to many of those muscles responsible for movement in the forelegs. (I know this sounds totally weird, but it is anatomically true).
Scientists have determined that there needs to be at least ½” room between the incisors where the bit is laid (so that a carrot could fit), to allow the horse to comfortably chew while bridled. There are two acupuncture points located in the headpiece area, which influence neck flexibility, back movement, and collection ability of the horse. If the flash or noseband is buckled too tightly, not only are these acupuncture points inhibited, but also the meridians which are located on either side of the head (the intestinal meridians). This further influences the flexibility of the haunches as well as proper breathing.
The Zygomatic Arch
A noseband which is too tight not only puts extra pressure on the neck at the headpiece; it presses directly on a nerve and also influences an acupuncture point. This nerve comes directly out at the zygomatic arch which is right under the noseband.
The noseband of some types of bridles mirrors the exit point of the branches of two nerves (“Nervus trigeminus” and “Nervus facialis”) at the “foramen infraorbitale” which can be felt at the top of the upper jaw bone. The bridle needs to be correctly fitted and buckled in order not to rub against these bone projections. Although pressure on bone won’t necessarily cause any damage to the bone itself, it will cause pain. So-called pressure necrosis will develop which can cause hair loss or the formation of white hairs – similar to when saddle pressure points cause issues.
The Lower Jaw
Many of the nerve insertion points are easily seen on the horse’s naked skull. One of the key ones can be seen exiting at the lower jaw at the “Foramen mentale”. It is close to the end of the horse’s mouth and extra care must be taken when the chain is attached so that it is not too tight.
Ear Salivary Gland
Pressure here will cause the horse to salivate, which leads to the chewing motion. If the bridle is too tight here and the horse feels resistance to being able to chew, enhanced saliva production will cause the horse stress and muscle tightening. The saliva will not be swallowed; it will simply drip out of the horse’s mouth. The hyoid lies beneath this gland, which is connected to a nerve in the ear. Too much pressure can furthermore impact the ability of the horse to maintain proper balance. There are more acupuncture points at the base of the ears where the browband sits. This acupuncture point ensures that both the jaw as well as the S-I joint remain mobile, and has an influence on the meridians responsible for the bladder, gall bladder, and small intestine – all of which further influence the movement of both the fore-and hindlegs.
In a study done at the University of Sydney the impact of too tightly buckled nosebands on chewing, eye temperature, and heartbeat rate was examined on 12 horses using a Swedish double bridle. With a too tightly buckled noseband, stress indicators were indicated by increased heartbeat and higher eye temperatures.
