What is the ethmoid bone and where is it located?

The ethmoid is a delicate, unpaired bone located centrally between the orbits. It forms part of the anterior cranial base and the upper nasal septum, featuring a sieve-like cribriform plate.

What are the main parts of the ethmoid bone?

The ethmoid bone consists of four key parts: Cribriform Plate, Crista Galli, Perpendicular Plate, and Two Labyrinths (containing ethmoidal air cells).

What is the function of the cribriform plate?

The cribriform plate separates the nasal cavity from the anterior cranial fossa. It is perforated by foramina that allow olfactory nerve filaments to pass from the nasal mucosa to the olfactory bulbs.

What does the crista galli do?

The crista galli is a vertical projection on the cribriform plate that provides attachment for the falx cerebri, a dural fold separating the cerebral hemispheres.

How does the perpendicular plate contribute to nasal anatomy?

The perpendicular plate projects downward from the cribriform plate to form the superior part of the nasal septum, helping divide the nasal cavity.

What are the ethmoid labyrinths and what do they contain?

The labyrinths are lateral masses on either side of the perpendicular plate. They contain ethmoidal air cells, classified as anterior, middle, and posterior groups.

What structures do the ethmoid labyrinths help form?

The labyrinths contribute to the medial wall of the orbit laterally and the lateral wall of the nasal cavity medially, featuring the superior and middle nasal conchae.

Ethmoid Bone – Cribriform Plate & Air Cells

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