Why would a riders tongue affect the horses tongue?

A number of years ago I had an interesting lesson with a student. The rider was struggling with getting a constant contact with her horse.  After watch both of them move around the arena for a while and seeing the mare, chomp, and fiddle with her tongue and bit I asked the rider “where is your tongue sitting in your mouth? To this the rider stopped the horse and said ” how the hell did you know that” so it turns out that this rider has a gap in-between one of her upper molars and she has a habit of twisting her tongue to place the tongue in the gap.  When I asked her to place her tongue softly onto the top of her mouth the horse became quite in its contact and as the lesson went on the horse began to move freer in the shoulders, the rider’s tonal quality of her arms into her hand and fingers became a soft tone.  So why is this so, I asked myself, and did some research. Why would the riders tongue affect the horses tongue so much? Well from what I have researched the hyoid bone is part of the tongue movement apparatuses as the omohyoid muscle origin site at the superior border of the scapula and can vary in location and in size, and at times the muscle also originates from the superior transverse scapular ligament. The attachment of the central tendon can be only to the clavicle or to the clavicle and the first rib. This image on the left is the human only; horses do not have a clavicle.  Wow I thought so when her tongue curls up a whole tension goes from her tongue down to her shoulder which must create a tension down her whole arm to her hand. This in turn puts a tension onto the rein and bit which travels onto the horse’s tongue, so guess what this also affects the horses hyoid bone and his omohyoid muscle into the shoulder causing the tight steps and fussy mouth. It’s a circle of tension.  Along with this is the TMJ joint of both parties again the hyoid bone, which is located in the throat latch area in the horse and upper throat of the human comes into play, as the hyoid connects to the larynx, pharynx and tongue and articulates with the temporal bone. With the horse it’s more complex as the TMJ also has the ear movement involved so mouthy horses, head shakers or sensitivity in this area could be a having tension in this area, if the rider is tight in the hyoid or TMJ it should be checked out. If a rider is constantly clamping the jaw I often get them to chew gum to help prevent this.   I was so fascinated by this I asked Sharon May Davies to show me the hyoid of the horse on my last course with her. I was amazed how big it was and yet frail it was. And so when the rider asked me “how did I know that”, it was a simple answer “the horse told me” but I did tell them the next day exactly why it was affecting her mare after doing some research. It’s all part of looking outside the box, to find a solution which works for the horse and can carefully guide the rider into a better place.  Sometimes the rider makes the coach look deeper as to the why something worked. Your gut feel can’t always be enough information for the rider. Also by having hard facts it takes away the mystical element of the lesson.