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Posterior Ethmoid Artery

arteria ethmoidalis posterior

The posterior ethmoid artery (PEA) is a smaller branch of the ophthalmic artery arising posterior to the AEA, passing through the posterior ethmoid foramen to supply the posterior ethmoid air cells, the posterior nasal roof, the superior nasal septum, and the dura of the adjacent anterior cranial fossa. It is smaller and more variable than the AEA and lies approximately 5-10 mm anterior to the optic canal — a critical measurement for endoscopic posterior ethmoidectomy.

Region: Head & Skull

Clinical Relevance

Clinical Notes

The posterior ethmoid artery is the key landmark for the optic canal in endoscopic skull base surgery: it lies approximately 5-10 mm anterior to the optic nerve at its canal, so identifying and preserving the PEA during posterior ethmoid dissection confirms that the surgeon is anterior to the optic nerve. The PEA supplies the posterior nasal septum contributing to the posterior epistaxis zone (alongside the sphenopalatine artery branches). In total ethmoidectomy and sphenoidectomy for sinonasal tumours, the PEA is divided after identifying the optic canal.

Pathology

Common Injuries & Conditions

Posterior Ethmoid Artery as Optic Canal Distance Marker

The posterior ethmoid artery within the posterior ethmoid foramen lies 5-10 mm anterior to the optic canal; endoscopic skull base surgeons use identification of the PEA to confirm that all dissection is anterior to the optic nerve during posterior ethmoidectomy and sphenoidotomy, preventing optic nerve injury.