Editing Ethmoid bone (section)

===Development===
The ethmoid is [[ossified]] in the cartilage of the nasal capsule by three centers: one for the perpendicular plate, and one for each labyrinth.

The labyrinths are first developed, ossific granules making their appearance in the region of the [[lamina papyracea]] between the fourth and fifth months of [[fetus|fetal]] life, and extending into the [[Turbinate|conchæ]].

At birth, the bone consists of the two labyrinths, which are small and ill-developed. During the first year after birth, the perpendicular plate and [[crista galli]] begin to ossify from a single center, and are joined to the labyrinths about the beginning of the second year.

The [[cribriform plate]] is ossified partly from the perpendicular plate and partly from the labyrinths.

The development of the ethmoidal cells begins during fetal life.