In parasympathetic movement patterns, the shoulder girdle- and specifically the AC joint- is what dictates the movement of the head. If you look at Image 1, this is the trapezius muscle. It attaches to the lower thoracic spine, the shoulder blades and behind the head.
If you were to look at a front image of it, you would see that it also loops over and attaches to the outer part of the collar bone.
One of the analogies we use a lot to show healthy movement patterns is that of a stingray, and if you look at the shape of the trapezius, it is very much of this shape. In movement, as the outer edges come forward, it allows the body to come into a curl.
As they come back, it facilitates the arch. In this way, the spine, head and shoulder girdle are all co-ordinating and working together to ensure no one part is compressed.
What you see commonly, however, is independent movement of the head separate to the shoulder girdle. Image 2 is an example of the shoulder girdle being rounded forward in a collapsed posture, and the head being forced upright. You can see how much pressure is then placed on the neck musculature and how it forces the thyroid cartilage (Adam’s apple) forward.
In Image 3, the head is looking down, but the shoulder girdle is fixed, again, placing a lot of pressure not only on the neck but also the spinal cord, another fight/flight motor pattern.
In functional movement, the distance between the ear hole and the AC joint will always stay the same; often, however, you see the distance getting shorter and longer as the two points move separately.
In rotation, we only have independent rotation at C1 and 2; this allows for the head to rotate at about 45 degrees (Image 4) before the shoulder girdle must go with it.
Image 5, however, shows common movement patterns where the head has moved beyond the 45-degree range, but the shoulder girdle remains fixed. This then requires each independent vertebrae in my neck to move and creates wear and tear on the spinal cord as a result.
Mobility of the fascial trains, understanding functional movement and motor repatterning not only allows the body to move in a way that’s sustainable but also avoids us firing off our fight flight nervous system through the repetition of sympathetic movement patterns.
As you ride, notice how often your head moves independent of the rest of your body. Notice when your gaze/ head turns beyond the 45-degree range. Does your ear and AC joint coordinate? Or are they working independently?
All valuable things to take note of, that have ramifications physically, but also mentally and emotionally- not to mention dramatically influence the ability for you to harmonise with your horse.