Computed tomographic imaging to determine the frequency of anatomical variations in pneumatization of the ethmoid bone

The present study was performed on axial and coronal CT scans of 212 patien ts. Scans were analyzed by an anatomist and a radiologist for the presence of Haller's cells, agger nasi cells, Onodi's cells and pneumatized crista g alli. Results demonstrated the presence of Haller's cells in 21.2%, Onodi's cells in 10.4% and pneumatized crista galli in 2.4% of patients. A pneumat ized anterior clinoid process was found in 0.5% of the patients. The data o btained in our study were compared with those reported in other anatomic an d radiologic studies.