|Image created by Chris Centeno, MD|
After my post last week about Understanding Vagal Tone, ClaireMarie Holman DC (Doctor of Chiropractic) reached out with a note about the vagus nerve that I thought would be worth sharing with you. (I’m including anatomical terminology here that I’ll translate afterward). Here’s how Dr. Holman begins:
The vagus nerve comes out of the brain and wraps around the transverse processes of Cervical 1 (C1) on the right and left before its descent to the organs below. This nerve is called the wanderer because of how very far it wanders from the brain. This was a very important point when I was studying in chiropractic college because if one has an injury where the head is hit [think whiplash or sports injury] all these can displace C1. Lateral blows to the head are serious also. Some people can even misalign C1 if they have a habit of sleeping on their arm at night, creating pressure on that transverse process.
If you look at the image above, you can see C1 (the first cervical vertebra, or the atlas) in yellow. It’s so wide that it almost looks like an extension of the skull, but there it is. The vagus nerve is singled out, and you can see it wrapping around the transverse process of C1 (the transverse processes are bony structures that stick out from the sides of the vertebrae—they serve as attachment points for muscles and ligaments of the spine). So you can imagine that if C1 is displaced, it would be a problem. Dr. Holman goes on to say:
Now the vagus nerve is displaced and all the same symptoms you mention [in the blog post] can exist. Once C1 is adjusted back into place the vagus nerve can then function at its optimum again. Can inversions reset C1? Perhaps. I would suggest trying inversions without any direct pressure on the top of the head. Directly doing a headstand on a misaligned C1 could be very serious. Same with Sun Salutations if done too rapidly and without awareness to the head.
As I mentioned last week, the vagus nerves (one emerging from each side of the brain, each wrapping around the transverse process on that side) serve virtually every organ in the thoracic and abdominal cavities, of special note, the heart (regulating pulse speed) and the stomach (stimulating acid production necessary for breaking down food for further digestion). If the nerve is displaced, or if there is extra pressure on it (the image above is excluding the sternocleidomastoid and scalenes, powerful muscles in the neck that a displaced nerve could get pressed into or crushed between) issues could develop further on down the line of this wandering nerve, such as difficulties with digestion or with regulating heart rate, or even lack of resiliency under stress.
Even more reason to consider your vagal tone, to think about spinal alignment in your yoga practice, and to be cautious with inversions that place pressure on the cervical vertebrae (perhaps practice Pincha Mayurasana, Forearm Balance, instead of Headstand). And, of course, seek help from a professional if you’ve had experience with whiplash and feel as if some of this rings a bell for you.
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