Nose blowing propels nasal fluid into the paranasal sinuses.

Intranasal pressures were measured in adults during nose blowing, sneezing, and coughing and were used for fluid dynamic modeling. Sinus CT scans were performed after instillation of radiopaque contrast medium into the nasopharynx followed by nose blowing, sneezing, and coughing. The mean (+/-SD) maximal intranasal pressure was 66 (+/-14) mm Hg during 35 nose blows, 4.6 (+/-3.8) mm Hg during 13 sneezes, and 6.6 (+/-3.8) mm Hg during 18 coughing bouts. A single nose blow can propel up to 1 mL of viscous fluid in the middle meatus into the maxillary sinus. Sneezing and coughing do not generate sufficient pressure to propel viscous fluid into the sinus. Contrast medium from the nasopharynx appeared in >/=1 sinuses in 4 of 4 subjects after a nose blow but not after sneezing or coughing.