Frontal sinus
Sinus frontalis
RespiratoryOrgansHeadLeft and right
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- What it is
- Air-filled space in the frontal bone behind the eyebrow, usually asymmetric and separated from its partner by a thin bony septum.
- Function
- Lightens the skull, adds resonance to the voice and may act as a crumple zone protecting the brain.
- Size
- About 3 cm high, 2.5 cm wide and 2 cm deep; absent at birth, it develops after about age 7.
- Clinical note
- It drains through the frontonasal duct into the middle meatus; infection can spread to the orbit or through the thin posterior wall to the brain.