3 Temporomandibular joint (TMJ)
The temporomandibular joint is the junction of the lower jaw (mandible) with the skull, and it has the most proprioceptive nerves in your horse’s entire body. It contributes to his spatial awareness-proprioceptive nerve endings, which make him aware of his movement and space around him. When your horse can’t move his lower jaw, he’ll struggle with his body awareness, which results in poor movement and performance. This joint also allows the movement of the lower jaw on the upper jaw, so your horse can:
Chew from side to side
Open his mouth to eat and yawn
Open up his airways via the forward movement of the lower jaw on the upper jaw as his head flexes.
Parts of the bridle to look at
If you fasten your horse’s noseband too tightly he’ll be unable to move his jaw. This can happen whatever type of noseband you use, so look at loosening the noseband by a hole or two. Also, question whether he really needs a flash noseband, for example, and consider trying him in a simple cavesson instead. While on the topic of nosebands, if it’s incorrectly positioned it can restrict your horse’s breathing by closing his nostrils. A horse is an obligate nostril breather and cannot breathe through his mouth. In addition, a tight noseband can compress the mucous membranes of the mouth against your horse’s teeth, resulting in discomfort or even pain.
Effect on your horse
If this area is compromised it’ll have a massive impact on his way of going. It can affect his balance and he may struggle with lateral movements. To try to relieve the tension in his muscles, your horse may go behind the bit, hollowing his back and shortening his stride.
The tightness of his noseband may affect your horse’s ability to do lateral work