Ethmoidal cells

In Men, the ethmoid air cells are numerous thin-walled cavities situated in the ethmoidal labyrinth and completed by the frontal, maxillary, lacrimal, sphenoidal, and palatine bones. They lie between the upper parts of the nasal cavities and the orbits, and are separated from these cavities by thin bony lamellae. They replace the ectoturbinates found in most domestic animals.