After teaching last night I had an impromptu chat about the misery of sleeping with a couple of students. I mentioned that I can only sleep in one position without deleterious effects. That position is on my right side with a pillow between my legs, my left hand on top of that pillow and my right arm bent with my right hand in between the two pillows under my head.
If I sleep in that that position I am good to go when I wake up. It took me a long time to develop the ability to sleep this way. My old form left my back a mess each morning due to my tendency to lie on my side/stomach with one knee hiked way up towards my shoulder when I sleep.
Re-training my body out of that shape took some doing but I got there eventually. While I think sleeping on the back is the best option for many people, with my open hips, my legs turn out to the sides too easily and that messes with my hip sockets. And anyway, I have never been able to fall asleep that way even if I wanted to.
But let’s return to the point of this post which is what happens to my shoulder when I sleep on my left side. On my right side, my right arm is will situated under my ribcage. On my left side the arm slips forward taking the shoulder blade with it.
There are a lot of muscles involved in this arrangement but I am only going to address two—the rhomboids and the pectoralis minor. On my good side with my arm correctly in place the rhomboids which connect the shoulder blade to the spine at the back are well aligned, and my pectoralis minor which connects the shoulder blade to the rib cage in the front are also correctly situated.
When I am on my troubled left side, the arm bone gets pulled forward taking the shoulder blade with it. In this environment the balance of the rhomboids and pectoralis minor is thrown out of whack with the rhomboids stretched too long and the pectoralis minor is shortened which puts it into its all too natural tight state.
The result of this imbalance is some kind of impingement of a nerve that leads to my fingers going numb. When I roll back onto my right side the numbness passes immediately.
After years of switching from side to side I am now trying to stay on the one side, which I don’t think is optimal but it is better than going numb. It is crazy just how much the position of my shoulder when I sleep can affect my nerves, my muscles, my quality of sleep… and even my mood when I wake up in the morning.