Frontal sinus

The frontal sinus develops from anterosuperior pneumatisation of the frontal recess into the frontal bone. Development begins late in intrauterine life or may start after birth (from one to twenty years and starts in the vertical segment). Pneumatisation develops from one to twelve years-old.

Gross anatomy

The frontal sinus has two chambers, one on each side, and they are almost always asymmetrical. However, three or more chambers may be present in ~10% (range 1.5%-21%). It is divided by thin bony intrasinus septa, usually off-midline and rarely dehiscent.

It drains via the frontal recess to the middle meatus via the ostiomeatal complex

Variant anatomy

  • may be absent (i.e. aplasia) or underdeveloped (i.e. hypoplasia): unilateral (4%) or bilateral (5%)
  • may be large: extending through zygomatic processes, orbital bones, and into the squamae

Head and neck anatomy
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Article Information

rID: 7037
System: Head & Neck
Section: Anatomy
Tags: refs, sinus
Synonyms or Alternate Spellings:
  • Frontal sinuses

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Cases and Figures

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    Case 1: normal sinuses on CT
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    Case 2: aplastic frontal sinues
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