6 types of fronto-ethmoidal cell: Type A - Agger Nasi cell + 1 fronto-ethmoidal cell (22.5%), Type B - Agger Nasi cell + 2 fronto-ethmoidal cells (72.5%), Type C - single massive cell pneumatizing cephalad into frontal sinus (2.5%), Type D - isolate d cell in the frontal sinus (1.25%), Type E - suprabulla cell (26.25%), Type F - interfrontal sinus septal cell (1.25%).