The present investigation presents the anatomical variations of the human paranasal sinuses using computed tomography scanning (CT scan). Paranasal sinus CT scans obtained from 300 subjects (120 male and 180 female) were analyzed. Their ages ranged from 15 to 55 years with a mean age (28.4±8.79).
The maxillary sinus revealed a number of anatomical variations in 30% of cases. They appeared in the form of septated sinus in 16%, sinus hypoplasia in 10 %, and the presence of a tooth in the sinus in 4% of the cases. Examination of the frontal sinus revealed extensive pneumatiza-tion of the sinus in 38%, hypoplasia in 26 % and aplasia in 4 % of the cases. CT examination of the sphenoidal sinus revealed sinus hypoplasia in 4%, extensive pneumatization of the sinus in 6 % and unseptated sphenoidal sinus in 10% of cases. Impression of the optic nerve on the wall of sphenoidal sinus was found in 60% of the cases. The internal carotid artery bulged within the lumen of the sphenoidal sinus in 50% of the cases. Anatomical variations of the ethmoid sinus detected by CT included Agger nasi cell (72%), sphenoethmoidal (Onodi) cell (70%), pneumatized middle turbinate (concha bullosa) (56%), enlarged ethmoid bulla (34%), infra-orbital ethmoidal (Mailer's) cell (30%), and paradoxically curved middle turbinate (20%).The uncinate process showed hypoplasia in 24%, elongation in 10%