My mom, having seen this in many old movies and TV shows, believed that if your hand fell off the bed while sleeping that you would die. Because of this, she slept with her hands curled tight to her chest.
A childhood belief about sleeping

others believed things like this
- When I was in elementary school, I believed my heart moved across my chest throughout the day.— Allison
- I believed that Santa Clause lived on the moon. I mean how else could he see you when you was sleeping? — danger101
- When i was little, i believed that if you slept with socks on, your feet would fall off.Anon
- I believed you could dry your hands with hot water, until i got a chance to try it.— A A RENN
- When I was little, I believed that slugs fell from the sky because they always came out when it rained.— JoJo
- I used to believed that when I went to sleep my heart took a rest too, and didn't pump at all while I slept.— Lara