Table 2.

IFAC Classification

Cell type	Cell name	Definition
Anterior cells	Agger Nasi Cell	The cell that sits either anterior to the origin of the middle turbinate or directly above the most anterior insertion of the middle turbinate into the lateral nasal wall
	Supra Agger Cell	Anterior-lateral ethmoidal cell located above the agger nasi cell
	Supra Agger Frontal Cell	Anterior lateral ethmoidal cell that extends into the frontal sinus
Posterior cells	Supra Bullar Cell	Cell above the bulla ethmoidalis that does not enter the frontal sinus
	Supra Bullar Frontal Cell	The cell that originates in the supra-bullar region and pneumatizes along the skull base into the posterior region of the frontal sinus. The skull base forms the posterior wall of the cell
	Supra Orbital Ethmoidal Cell	An anterior ethmoid cell that pneumatizes around, anterior to, or posterior to the anterior ethmoidal artery over the roof of the orbit
Medial cells	Frontal Septal Cell	Medially based cell of the anterior ethmoid or the inferior frontal sinus, attached to or located in the interfrontal sinus septum