Ethmoidal sinus

The ethmoidal sinuses (or ethmoidal air cells) are one of the four paranasal sinuses. They are located within the ethmoid bone. They are present at birth and they develop rapidly from 0-to-4 year-old; they further mature from 8-to-12 year-old during puberty.

Gross anatomy

A collection of air cells (3-18 in number) divided by bony septa within the lateral mass, or labyrinth, of the ethmoid bone

Separated into anterior and posterior groups by the basal lamella, the lateral attachment of the middle turbinate to the lamina papyracea. Some authors describe 3 groups of sinuses, the anterior, middle and posterior ethmoidal sinuses.

The anterior ethmoidal air cells drain to the hiatus semilunaris and middle meatus via the ethmoidal bulla, which form parts of the ostiomeatal complex. The posterior ethmoidal air cells drain to the superior meatus and sphenoethmoidal recess 2.

Some of the ethmoidal air cells have their own name, because of their importance in surgical procedures or their involvement in head and neck pathologies:


The posterior ethmoidal sinuses, along with the sphenoid sinus, is supplied by the posterior ethmoidal nerve whereas the middle and anterior ethmoidal sinuses are supplied by the anterior ethmoidal nerve. Both theses nerves being extraconal branches of the nasociliary nerve, a branch of ophthalmic division of the trigeminal nerve

Head and neck anatomy
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Article information

rID: 25383
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:
  • Ethmoidal air cell
  • Ethmoidal sinuses
  • Ethmoid sinuses

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