Variability of the bony structures located in the maxillary sinus, and of the lateral nasal wall topography, have practical significance during surgical procedures conducted by maxillofacial surgeons or otolaryngologists. The retrospective analysis of 111 computed tomography examinations of patients (52 male and 59 female) diagnosed in our institution was made to evaluate anatomical variations of the maxillary sinus. In the study the frequency of the Haller cell was 29/222 (13%), and the prevalence of one or more septa per sinus was 49/222 (26%). The infraorbital recess was found in 6/222 (3%) of cases. The mean width of the nasal duct was enlarged at the side where the Haller cell was present (p < 0.01) or where bony septa were absent in the maxillary sinus (p < 0.01). Bony structures of the maxillary sinus and changes in topography of the lateral nasal wall should compel surgeons to carefully analyze the computed tomography scans before operations in this area.