[donmoore]

As I look at the above graphic and think about it, I think there are two issues in filling the middle ears. First you have to have fluid over the opening of the Eushtian tubes before trying to equalize. Second the air in the middle ear needs to come out. This may explain why I was able to push the fluid in while inverted, with head down. What is hard to see on the graphic is the Eustician tubes are going to the sides (forward and behind the graphic) of the head and a little up so they will drain fluid when the head is upright.

Maybe when inverted it allows the gravity of the fluid to go down and let air bubble up and out.

Anyone have a good 3-D graphic of Naspharynx, Eustachian tubes, and middle ears?
don