Does sleeping on your back cause sleep paralysis?

Sleep paralysis: This is a normal part of sleep and in fact must be present during rem sleep or there will be a medical condition known as rem sleep behavior disorder. Sleeping on ones back has nothing to do with it.

Sleep paralysis: During REM sleep, when you are dreaming, your body is paralyzed so you do not act out your dreams and hurt yourself. Sometimes people wake up out of REM but their muscles are still paralyzed. It is very alarming but it goes away on its own. Sleeping on your back is not the cause of sleep paralysis.