[Experimental studies of the physiology of the paranasal sinuses]

The mucociliary clearance of the maxillary sinus mucosa was studied by 99mTc-SC in 38 healthy subjects. The mucociliary transport rate was relatively constant under physiological conditions so that it was possible to describe a normal range with a narrow variation. This range can be used to estimate the physiological responses of the mucociliary apparatus, and to define pathological disorders. In 3 cases we saw a slow clearance which has never been described before in the sinuses. In our experimental study we showed that the mucociliary activity of the sinuses is not only a mechanism to clean the mucosa, but is moreover a controlled system which can be activated by a physiological stimulus. After the stimulation the production of mucus and its outflow to the nose increased. Physiological and phylogenetic aspects of the existence of the sinuses in vertebrates and man are discussed.