Understanding Your Sinuses

Your sinuses are air-filled spaces between the bones in your head. They have small openings that connect to the nasal cavity. The sinuses make mucus that drains into the nose. This helps keep the nose moist and free of dust and germs.

Sinuses showing frontal sinus, maxillary sinus, middle meatus, septum, and turbinates

Side image showing frontal sinus, ethmoid sinuses and sphenoid sinus

Lining of the sinus showing cilia and mucusParts of the nasal cavnity

  • The septum is the wall of cartilage and bone in the center of the nasal cavity.

  • The middle meatus is the intersection between the sinuses.

  • Turbinates are ridges on the sides of the nasal cavity.

Cilia keep sinuses clear

Air circulates freely though healthy sinuses. Tiny, hairlike structures called cilia line the sinuses. Cilia move the thin, watery mucus through the sinuses and into the nose. Sinuses are healthy when they drain freely. Sinus drainage can be blocked if the sinus lining is swollen or if mucus is too thick. Cilia that are damaged or don’t work correctly can also lead to problems with drainage.

Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Online Medical Reviewer: Turley, Ray, BSN, MSN
Last Review Date: 5/16/2014
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