[Drainage of the middle ear].

Otitis media with effusion occurs very frequently in childhood and usually heals without therapy. The condition is thought to be due to a higher susceptibility to infections of the upper respiratory tract and the fact that the Eustachian tube is not yet functioning perfectly at that age. Many authors explain this astonishingly high rate of spontaneous recoveries by tube malfunction alone, never even considering a middle ear clearance system. It is known from the paranasal sinuses that the cavities are regularly and continually cleaned according to very precise rules. In in-vivo experiments with guinea pigs the author proved that there is an obvious similarity between the paranasal sinus and the middle ear as far as the clearance system is concerned. By applying tracer substances to the middle ear mucosa the usual drainage pathways out of the middle ear into the Eustachian tube, and the different rates of drainage were very precisely defined.