<prompt> Onodi cells and haller cells are seen in relation to:Optic nerve and floor of orbitOptic nerve and frontal sinusOptic nerve and ethmoid air cellsOptic chiasma and nasolacrimal duct  <response>: Onodi cell is the posterior most posterior ethmoid cell extending lateral to the sphenoid sinus. While removing disease from the Onodi cells there are chances of injury to optic nerve and internal carotid which lie in the vicinity. The posterior ethmoidal cells in the floor of orbit are known as Haller cells. 