Talking about tonic and phasic muscle actions. The new-born foal's first action is to lift head and withers and stand up. After a search for the mare's milk, the second action is to lift the head into horizontal position and suck. Sucking involves a distinct movement of the tongue.
Viewing Peter Goody, "Horse Anatomy".
When the horse lifts the head the following muscle systems are activated, regardless of the head's position.
- the brachiocephalic, which connects upper head and upper arm. In the horse unlike in the human the upper arm is incorporated in the body.
- the omotransvers, which connects upper head and neck vertebrae one to four to the upper arm.
These muscles lift the horse's front legs and shoulders. Their antagonist connects the center of the upper arm to the upper line in, before and behind the rider's seat and pulls them back. It is obvious why thy the counted walk, nose in the sky and the forward walk nose dropped, in both case the yes joint being closed, are pairs in suppling the horse.
In the head's horizontal position the following muscles are stretched regardless of the head's elevation.
- the sternohyoid, which connects the root of the tongue and the sternum. It pulls the tongue back and impacts the interactions of swallowing, voice and breathing .
- the sternomandibular, which connects jaw and the sternum to bilaterally pull down head and neck. Unilaterally it flexes head and neck towards the sides.
- the omohyoid, which connects the root of tongue and hyroid with ribs and shoulders and pulls tongue and hyoid back .
It becomes obvious why turning the nose into the sky speaks to the tongue, the position of the sternum and the shoulders. Via the long ligament's release it impacts as well the sacrum and the closing of the croup.
