Ethmoidal air cells

Dr Craig Hacking and Dr Maxime St-Amant et al.

The ethmoidal air cells (or less commonly, the ethmoidal sinuses) form one of the four pairs of paranasal sinuses. They are located within the single, midline ethmoid bone.

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

They are separated into anterior and posterior groups by the basal lamella, the lateral attachment of the middle turbinate to the lamina papyracea. Historically the ethmoid sinuses were subdivided into 3 groups of air cells: the anterior, middle and posterior ethmoidal air cells. The middle group are now incorporated into the anterior group.

The anterior ethmoidal air cells drain to the hiatus semilunaris and middle meatus via the ethmoid bulla, which forms 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:

From the ophthalmic branch of the internal carotid artery, the supraorbital, anterior and posterior ethmoidal arteries supply the ethmoid air cells with the sphenopalatine artery (a branch of the maxillary artery) also contributing. Thus, the ethmoid air cells are supplied by branches of both the internal and external carotid arteries. 

Lymph from the ethmoid air cells drains to the submandibular and retropharyngeal group of nodes.

The posterior ethmoidal air cells, along with the sphenoid sinus, is supplied by the posterior ethmoidal nerve whereas the anterior ethmoidal nerve supplies the anterior ethmoidal air cells. Both these nerves being extraconal branches of the nasociliary nerve, a branch of the ophthalmic division of the trigeminal nerve.

They are present at birth, and they develop rapidly from 0-4-year-old. They further mature from 8-12-year-old during puberty.

Head and neck anatomy
Share article

Article information

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

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Figure 1: in blue on annotated CT
    Drag here to reorder.
  • Drag
    Normal ostiomeata...
    Figure 2: normal ostiomeatal complex diagram
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.