I found this video on Facebook. It belongs to Patrica Bensenbach.
The audio is in German, but I found you don't really need to words to understand the video.
When Peggy Cummings described the movement in the horses head and neck as a slight "oscillation" I immediately pictured a 3D computer image of a horse at the walk. I don't know if I have seen this video somewhere on the Internet before, or it's just a giant coincidence that it matches the image in my head, but I almost jumped out of my seat on the bus when I pulled it up on my cell phone.
I believe that blue line down that goes from the horses poll down to its tail is the Nuchal Ligament. The video seems to show the stresses placed upon the horses body when it is over flexed in the head and neck. I find the highlight of the poll to be particularly fascinating.
I love watching the movement of the horse skeleton in the trot starting at the 2:29 mark. The horses head and neck are in what I would call the "neutral" position. Not over flexed or above the bit. The movement is elastic and fluid. What really drew my eye was the slight oscillation of the horses head right at the poll. If you look at the cheek bones of the horse you can see them slightly rocking back and forth in pattern with the hind legs just as Peggy described it. That is almost identical to the image I have been carrying around in my brain for the past two weeks.
One morning last week on my way to the bus stop I couldn't let go of this image. So I tried it, just to see what it would feel like. As I walked, I slightly turned my head to the left every time I brought my left foot forward,I turned my head to the right in conjunction with the right foot. Within 5 steps I found the rhythm. My jaw started to soften, my neck was no longer stiff. I found I could not clench my teeth even if I wanted to. I crested the top of the hill on my way to the bus without even realizing it, the hill climb was effortless.
Pretty amazing stuff!