The relationship of the nasal and the antral ventilation was studied with a plastinated model of a human nose. The effects of adenoidal hyperplasia and septal deviations on the antral ventilation were measured. It could be demonstrated that the aerodynamic effect of an obstruction within the nasal cavity largely depends on the localisation of the stenosis (anterior or posterior to the maxillary ostium). Additionally, the influence of an ostial obstruction on the antral ventilation was examined in dependence on the nasal ventilation. We were able to demonstrate that the antral pressure variations not only reflect the ostial function but as well the total aerodynamics of the upper respiratory tract. From this point of view we discuss diagnostic and therapeutic conclusions.