Mucociliary flow in the canine frontal sinus.

The mucociliary flow in the frontal sinus of dogs is in a spiral pattern from medial to lateral. The final evacuation of mucus is through the ostium positioned anteriorly. Mucus flow rate is most rapid in the areas of the ostium and slowest in the area of the intersinus septum. Mucus flow patterns remain the same despite removing the intersinus septum and blocking one frontal sinus ostium. Mucociliary flow rate, however, appears to be diminished in the reoperated frontal sinus. Mucus does not appear to migrate readily across the intersinus septal areas when the septum has been removed and one nasofrontal duct is obstructed.