Types of ethmoid sinus morphology on the basis of computed tomography examination.

The aim of the study was the application of computed tomography (CT) in the evaluation of types of ethmoid morphology. The material consisted of 197 CT examinations performed, using the Somatom AR.T (Siemens) CT scanner, in patients referred for CT for reasons other than sinus pathology. The examinations were performed in 2-mm contiguous axial scans. Ethmoid morphology was evaluated by means of classification into 3 types according to the degree of aeration and the relationship of the anterior ethmoid cells to the lacrimal sac on transversal scans. The most common was the II type (medium relationship to the lacrimal sac) found in 38.32% of the cases. Type III (large ethmoid sinus extending in front of the lacrimal sac) occurred in 32.49% of the patients, while the smallest sinus (Type I) was detected in the remaining 29.19% of the cases. In almost 1/5 of the cases asymmetry of the bilateral ethmoid anatomy was noted. It was concluded that CT examination was useful in the evaluation of ethmoid sinus morphology in respect to the lacrimal sac.