Editing Ethmoid bone (section)

==Structure==
The ethmoid bone is an anterior cranial bone located between the eyes.<ref name="Saladin">{{cite book |last=Saladin |first=Kenneth S. |title=Anatomy and Physiology: the Unity of Form and Function |publisher=McGraw Hill |edition=7th |location=New York |year=2015 |isbn=978-0-07-340371-7 }}</ref> It contributes to the medial wall of the orbit, the nasal cavity, and the nasal septum.<ref name="Saladin" /> The ethmoid has three parts: [[cribriform plate]], [[ethmoidal labyrinth]], and [[Perpendicular plate of ethmoid bone|perpendicular plate]]. The cribriform plate forms the roof of the nasal cavity and also contributes to formation of the [[anterior cranial fossa]],<ref>{{Cite web|url=https://www.anatomynext.com/ethmoid-bone|title=Ethmoid bone|website=www.anatomynext.com|language=en|access-date=2018-03-01|archive-date=3 September 2020|archive-url=https://web.archive.org/web/20200903013615/https://www.anatomynext.com/ethmoid-bone/|url-status=dead}}</ref> the ethmoidal labyrinth consists of a large mass on either side of the perpendicular plate, and the perpendicular plate forms the superior two-thirds of the nasal septum.<ref name="Saladin" /> Between the [[orbital lamina of ethmoid bone|orbital plate]] and the [[nasal concha]]e are the [[ethmoidal sinus]]es or ethmoidal air cells, which are a variable number of small cavities in the lateral mass of the ethmoid.<ref>{{cite book |title=Illustrated Anatomy of the Head and Neck |last1=Fehrenbach |last2=Herring |publisher=Elsevier |year=2012 |page=52 }}</ref><ref>{{cite book |title=Human Anatomy |last=Jacobs |publisher=Elsevier |year=2008 |page=210 }}</ref>

=== Articulations ===
The ethmoid [[Articulation (anatomy)|articulates]] with thirteen bones:

* two bones of the neurocranium—the [[frontal bone|frontal]], and the [[Sphenoid bone|sphenoid]] (at the [[Body of sphenoid bone|sphenoidal body]] and at the [[sphenoidal conchae]]).
* eleven bones of the viscerocranium—, two [[nasal bones]], two [[maxillae]], two [[lacrimals]], two [[palatine bone|palatines]], two [[inferior nasal concha]]e, and the [[vomer]].

===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.