One hundred computerized tomography (CT) scans from patients with rhinosinusitis were compared with 100 CT scans from patients with intraorbital disease. There were no significant bony anatomical differences between the rhinosinusitis group and the control group and there remained no difference when 17% of the control group, who were incidentally found to have mucosal changes, were excluded from the control data. None of the anatomical bony variations compared between the two groups showed any significant difference, including any associated with narrowing of the ostiomeatal complex (P = 0.41). Eight per cent of all subjects (n = 200) had Onodi cells and 7% had an asymmetrical anterior skull base. In conclusion, bony anatomical variations appear not to influence the prevalence of rhinosinusitis. Intrinsic mucosal disease is probably of much more importance than the bony anatomy.