From my limited understand of balance, a large part of it comes from an organ in the ear which detects the movement of fluid in differently oriented canals. The fluids move depending on gravity and acceleration, and the brain gets information that it uses to keep it’s balance.
How does the sense make out the difference between tilting your whole body and tilting only your head? Wouldn’t those have a similar effect on the ear fluid system? If I tilt my body to the right and my head to the left, the fluids in my ear would be the same as if I was just standing upright. Is that information combined with signals from the muscles to get a clear idea of the situation or does the information come from somewhere else?