Abstract
In order to develope the more effective method of the aerosol therapy, it is very important to investigate the flow patterns in the nasal cavity and the paranasal sinus, especially in a maxillary sinus, precisely. Then, flow visualization was done by using a dry-ice and a glycerin-water mixture mist as the tracers. As a result, there exists very weak flow from the nasal cavity to the maxillary sinus through the small opening of the maxillary sinus. It was also clarified that the flow pattern of the nasal cavity is so reasonable and complex. There exists two swirls at least. On the other hand, the flow pattern in the paranasal sinus is very weak, simple and almost laminar.
