THE NECK OF THE RIDDEN HORSE
The muscles of the neck play an important function when we ask the horse to balance and start collecting. If we want the horse’s hind legs to take some weight and the back to lift, the neck needs to play its part too. In collected movement, the horse is actively using his abdominal muscles, iliopsoas complex, and the muscles under the base of the neck. The long back muscle and the muscles of the upper neck play a more passive role in this type of movement. Going into the architecture and function of all the neck muscles would be more suitable for a book than an article, so we will try to keep things simple. The main muscles that affect the movement of the horse’s neck can roughly be divided into two groups: the muscles above the vertebrae (m. rhomboideus and m. trapezius) and the muscles below the vertebrae (m. scalenus and m. longus colli). Note that the muscles below the vertebrae are not the big bulky muscles on the underside of the neck (m. brachiocephalicus). They are much smaller and lie much deeper than the superficial muscles. The first group of muscles works close together with the long back muscle (m. longissimus dorsi) and the second group works alongside the abdominal muscles (m. rectus abdomens, m. transversus abdominis). Both muscle groups need to work alternately and harmoniously to create healthy movement. These two muscle groups are antagonistic, which means they function in opposite ways to one another when actively contracting. When the horse actively contracts the muscles under the base of the neck, the base of the neck will lift, aiding the horse to lift his back and make his neck appear longer. Some refer to this as the horse lifting through the withers. When the horse actively contracts the muscles above the vertebrae, the base of the neck lowers and the back will become hollow because the function of the upper neck muscles is closely connected to the function of the long back muscle. A horse with a lowered base of the neck cannot raise his back properly. In the ridden horse, the goal is to encourage the horse to lift the base of the neck, as this is a prerequisite for balanced movement. This is done by avoiding the situation where the horse would hold his upper neck muscles tense.
WHAT CAN GO WRONG?
The neck is a body part that a lot of riders want to have complete control over. Focusing too much on headset, a lot of riders will try to use their hands to force the horse’s head and neck into a desired frame. This can be done with either too much rein aids or the use of draw reins. When we force the horse to keep his head and neck in one position during movement, we are inevitably overburdening certain muscles of the neck. This will eventually lead to tension all over the neck and cause the back to stiffen too. In the long run this translates to back pain, lameness and degenerative joint disease in the neck vertebrae. If the horse is ridden with a shortened neck and a lot of pressure on the bit, the lower neck vertebrae are positioned differently and more compressed than if the neck was free to move. Because of this incorrect riding often results in bony changes to the lower cervical vertebrae. Tense muscles and improper biomechanics can cause the neck vertebrae to become misaligned, limiting movement between the joints. This causes the whole neck to become stiff and unable to function properly. This lack of mobility will trigger a chain of compensation, which lead to problems all over the body. Problems in the neck area should therefore never be taken lightly as they can negatively impact the whole body.
Riding with a shortened neck compresses the vertebra, prevents the horse from lifting the base of the neck and impedes healthy movement.
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Part 3 of this article looks at what you can do to keep your horse’s neck healthy and developing nicely.