Anterior ethmoidal notch

Radiopaedia • CC-by-nc-sa 3.0 • de

The anterior ethmoidal notch contains the anterior ethmoidal artery and has significant rates of anatomic variation that put the artery during functional endoscopic sinus surgery (FESS).

Gross anatomy

The anterior ethmoidal notch lies in the medial wall of the superomedial orbit, adjacent to the anterior ethmoid air cells.

Radiographic features

CT
  • the notch can be identified bilaterally in 95-100% of patients on coronal reformats, and when not seen bilaterally is present unilaterally

Related pathology

During FESS the anterior ethmoidal artery is considered "protected" if the notch is adjacent to the fovea ethmoidalis or lateral lamella. The anterior ethmoidal artery is at increased risk of injury during FESS if there are pneumatized supraorbital anterior ethmoid air cells (occurs in ~30% of patients) .