MedlinePlus Medical Encyclopedia: Sinusitis

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Sinusitis

Sinusitis refers to inflammation of the sinus cavities, which are moist, hollow spaces in the bones of the skull. There are four pairs of sinuses:

Frontal sinuses
Maxillary sinuses
Ethmoid sinuses
Sphenoid sinuses (not shown in illustration)

If the opening from a sinus cavity becomes plugged, the flow of mucus is blocked and pressure builds up, causing pain and inflammation.

Update Date: 7/25/2007

Updated by: James L. Demetroulakos, M.D., F.A.C.S., Department of Otolaryngology, North Shore Medical Center, Salem, MA. Clinical Instructor in Otology and Laryngology, Harvard Medical School. Review provided by VeriMed Healthcare Network.

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