[Importance of the eustachian tube in middle ear function].

This paper reviews ventilation, drainage and protection as Eustachian tube functions which influence the middle ear. The most frequent etiologic factors which cause disorders of these functions and possible consequences on the middle ear are illustrated. The paper also reviews classification of the degree of Eustachian tube ventilation disorders, the most frequent causes of its dysfunction, as well as methods which are used for checking Eustachian tube ventilation.