A Detailed Assessment of Variations of Ethmoid Roof, Olfactory Fossa, and Anterior Ethmoidal Artery on CT Scan of Paranasal Sinuses of 200 Patients.

To study and analyse the variations in ethmoid roof anatomy and estimate the anatomical location and variations of AEA on CT scans. The study is conducted on 200 patients for detailed analysis of the olfactory fossa (OF) depth, supraorbital pneumatisation, and AEA location and distance from the skull base. In our study, Keros type II was predominant type seen followed by type I. Asymmetry was noted in 32/200 subjects (16%). The anterior ethmoidal artery (AEA) canal was seen in 341/400 sides (85.2%). We found Keros type II was the most common type in our study. We also found grade I anterior ethmoidal artery as the most common variant and the dangerous grade III anterior ethmoidal artery was least common type found in this study, and there was a significant association of Keros type II with increasing anterior ethmoidal artery grading.