Credit: Getty Images. An exhalation delivery system appears to more effectively apply topical steroids to nasal polyps located in the ostiomeatal complex. This article is part of MPR’s coverage of the ...

There are 4 sets of sinuses ordinarily present in humans, but congenital absence or hypoplasia of one or more sinus cavities is not uncommon. The maxillary and ethmoidal sinuses form during the third ...