It is also called the nasoturbinal concha and the nasal ridge. In 90% of patients an anterior ethmoidal cell (called the "agger nasi cell") can be found in the lacrimal bone below the agger nasi ridge.[1] An enlarged agger nasi cell may encroach the frontal recess area, constricting it and causing mechanical obstruction to frontal sinus drainage. The agger nasi cell may be removed during sinus surgery to open an obstructed frontal sinus drainage pathway.