A i.e. Optic nerve and floor of orbit Agger nasi cells are medial relations of lacrimal sac & duct; Haller's cells develop medially beneath orbital floort2 and Sphenoethmoid or Onodi cells is intimately related to optic nerve & canal and internal carotid aeryQ. It may contain tuberculum nervi optic, where the optic canal bulges into the wall of onodi cell. And optic nerve injury is a devastating complication of endoscopic sinus surgery, paicularly if a sphenoethmoid cell is present.