Also found in: Dictionary, Encyclopedia.
a mass of air cells with thin bony walls forming part of the lateral wall of the nasal cavity; the cells are arranged in three groups, anterior, middle, and posterior, and are closed laterally by the orbital plate which forms part of the wall of the orbit.
ectethmoid/ec·teth·moid/ (ek-teth´moid) ethmoidal labyrinth.
ectethmoid(ĕk-tĕth′moyd) [″ + ethmos, sieve, + eidos, form, shape]
The lateral mass of the ethmoid bone.