Ethmoid bone

A key structure within the skull that contributes to the formation of the nasal cavity and the orbits of the eyes.

The ethmoid bone is a delicate, spongy bone located at the roof of the nasal cavity, between the eyes. It plays a vital role in separating the nasal cavity from the brain and supports the nasal structures. This bone is part of the cranial skeleton and consists of a horizontal plate known as the cribriform plate and two vertical plates forming the perpendicular plate and the ethmoidal labyrinth.

Terminologia Anatomica

os ethmoidale

System

Skeletal system

Function

The ethmoid bone serves several essential functions within the body. Primarily, it creates a robust structural framework for the nasal cavity, facilitating the separation of the brain and the respiratory system. This anatomical arrangement ensures that harmful pathogens and toxic substances in inhaled air are prevented from reaching the sensitive neural tissues of the brain. Additionally, the ethmoid bone contains numerous small openings in its cribriform plate, allowing for the passage of olfactory nerves, which are key in the sense of smell. The presence of the ethmoidal labyrinth, containing ethmoidal sinuses, further aids in reducing the weight of the skull while contributing to the function of the respiratory system by humidifying and warming the incoming air.

Location

Positioned between the frontal bone and the sphenoid bone, the ethmoid bone's location is central to the skull's anatomy. It resides posterior to the nasal bones and anterior to the sphenoid, creating an integral connection between the cranial cavity and the nasal cavity. The cribriform plate extends horizontally across the upper part of the ethmoid, while the perpendicular plate descends vertically into the nasal cavity, forming a portion of the nasal septum. This unique positioning places the ethmoid bone at a critical junction where respiratory, olfactory, and cranial functions overlap, making it a crucial element of the upper skull.

Did You Know?

The ethmoid bone is one of the lightest bones in the human body, which aids in reducing overall skull weight.
The cribriform plate contains multiple tiny perforations that olfactory nerves pass through, allowing for the sense of smell.
Inflammation or infection of the ethmoid sinuses can lead to ethmoiditis, a condition that can affect sinus function and overall health.