Ostiomeatal complex

Dr Maxime St-Amant and Dr Henry Knipe et al.

The ostiomeatal complex (OMC) or ostiomeatal unit (OMU), sometimes less correctly spelt as osteomeatal complex, is a common channel that links the frontal sinus, anterior ethmoid air cells and the maxillary sinus to the middle meatus, allowing airflow and mucociliary drainage. 

The ostiomeatal complex is composed of five structures:

  1. maxillary ostium: drainage channel of the maxillary sinus
  2. infundibulum: common channel that drains the ostia of the maxillary antra and anterior ethmoid air cells to the hiatus semilunaris
  3. ethmoid bulla: usually a single air cell that projects over the hiatus semilunaris
  4. uncinate process: hook-like process that arises from the posteromedial aspect of the nasolacrimal duct and forms the anterior boundary of the hiatus semilunaris
  5. hiatus semilunaris: final drainage passage; a region between the ethmoid bulla superiorly and free-edge of the uncinate process

There is a wide range of anatomical variants that affect the many structures that compose the ostiomeatal complex and are not pathological in themselves but their presence can result in disease. See main article, ostiomeatal narrowing due to nasal anatomical variation, for the complete list. 

Anatomy: Head and neck

Anatomy: Head and neck

Article information

rID: 27335
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:
  • Osteomeatal unit
  • Osteomeatal complex
  • Ostiomeatal unit
  • OMC
  • OMU

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Cases and figures

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