The Hyoid Apparatus
Every muscle in the horse’s body is connected to the hyoid apparatus, a collection of small bones that form a Y shaped structure sitting between the cheeks at the base of the skull.
The base of the tongue is attached to the hyoid – a horse that cannot move its tongue cannot move its body freely.
The muscles of the ventral neck are attached to the hyoid – tension here restricts shoulder movement and places strain on the TMJ interfering with balance and proprioception.
The pelvic muscles are attached to the hyoid via the abdominal muscles and pectoralis muscles – a horse with ventral muscle chain dysfunction cannot engage its hind limbs.
Here’s Belinda on the subject:
“The Hyoid apparatus, TMJ and ventral chain functioning are often discussed in the online Masterclasses. This apparatus is incredibly fascinating because it is so delicate, and so interconnected.
This is why we need to be so careful with the weight we place on the reins.
We should always be aiming for contact that is only just feeling the tongue's movements because if we exert any additional pressure here, we begin to create problems. This structure is extremely breakable."