URL of this page: //www.nlm.nih.gov/medlineplus/ency/imagepages/19315.htm

Sinusitis

Sinusitis

Overview

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 7/30/2012