Do you know the function of your horse's hyoid bone and how it affects movement?
I discuss some of the common signs that your horse could benefit from a hyoid release.
The main function the hyoid is to support the tongue. It also places a role in balance.
A horse's hyoid is made up of pairs of stylohyoid, epihyoid, ceratohyoid and thyrohyoid bones, with a central basihyoid bone. The central basihyoid bone supports the lingual process where the tongue attaches. The stylohyoid connects with the temporal bone to allow cranial and caudal movement, much like a pendulum. The base of the tongue is linked to the lingual process, soft palate and pharynx.
Every muscle in the horse's body eventually connects to the hyoid.
Multiple muscles attach to the hyoid bone that can affect its position and shape. The main attached muscles are the omohyoideus that originates on the sub-scapular fascia near the shoulder joint and inserts on the basihyoid bone, sternohyoideus which originates on the sternum and inserts on the basihyoid bone , and the sternothyroideus again originating on the sternum but inserts on the thyroid cartilage.
The sternohyoideus and sternothyroideus muscles directly connect the horse’s tongue and mouth to its chest. These connections continue through the pectorals along the abdominals and into the pelvis.
The omohyoideus connects to the shoulder linking into the fascial chain that runs from the head, along the neck and all the way to the toe of the hind limb. This explains riding 'leg to hand' and how the connection of your leg aid activates your horse's hind end.
We can't forget about the poll of the horse. The occiputohyoid muscle connects the hyoid to the poll creating a link from the shoulder through the hyoid to the poll. The connection continues through the nuchal ligament and the muscles that make up the horse's top line back to the hindquarters.
GREEN: sternohyoideus & sternothyroideus
HOW THE HYOID AFFECTS YOUR HORSE'S MOVEMENT
Now we know the hyoid is not only directly connected to the tongue, forelimbs and poll, it also indirectly connects to the horse's hind end. Any restriction, pain or dysfunction of the hyoid may impact forelimb movement possibly leading to a shortened stride. This then can cause an inability to engage the hindquarters.
Other signs of a dysfunction in the horse's hyoid are: