Internal Thumping

Most nights, just as I’m dropping off to sleep, I “hear” a loud thump. It happens fairly regularly and usually manages to scare the bejesus out of me. The first few times ended up with me wandering the house trying to find out what had fallen over.

It’s most odd. The closest thing I can find is the myoclonic twitch but that’s normally associated with the legs/arms/body. Is it possible I’m experiencing these in some small internal muscle near or in my ear/head???

Just wondering.