Abstract
The olfactory fossa (OF) is a depression in the anterior cranial cavity whose floor is formed by the cribriform plate of ethmoid, bounded laterally by the lateral lamella of cribriform plate and medially by crista galli. Keros categorized the olfactory fossa depth into 3 types. For a successful endoscopic sinus surgery, the surgeons should pay attention to the details when dealing with the complex anatomy of the paranasal sinuses (PNS) and skull base. The aim of this study was to describe the distribution of Keros classification of the height of ethmoid roof among Saudi population by using multidetector computed tomography (MDCT). This was a retrospective study conducted on 511 patients (360 males and 151 female) referred for MDCT assessment of PNS over a two-year period. The mean age of our patients was 34.47 +/- 10.69 years, aged between 18 and 79 years. Patients with nasal trauma, surgeries or any pathological diseases affecting the ethmoid roof were excluded from the study. Keros type II was the commonest presentation observed in 53.2% of cases, followed by type I in 12.5%, then type III in 11.7% of cases. Out of the 511 patients analyzed, 115 (22.5%) cas- es had asymmetry (different types of OF) on both sides. Conclusion: The majority of studied Saudi adult population showed Keros type II (53.3%), followed by type 1 (12.5%). Keros type III was seen in 11.7% among the studied population.