Sagittal section of skull. (Ethmoid bone visible as white structure to left.)
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| colspan="2" |Lateral wall of nasal cavity, showing ethmoid bone in position.
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|Latin
|colspan="2"|os ethmoidale
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|[[List of subjects in Gray's Anatomy:36#Gray.27s_page_.23|Gray's]]
|colspan="2"|[subject #36 ]
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|Origins
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|Insertions
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|Articulations
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|MeSH
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|Dorlands/Elsevier
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The ethmoid bone is a bone in the skull that separates the nasal cavity from the brain. As such, it is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction.
The ethmoid bone is very delicate and is easily injured by a sharp upward blow to the nose, such as a person might suffer by striking an automobile dashboard in a collision. The force of a blow can drive bone fragments through the cribiform plate into the meninges or brain tissue. Such injuries are often evidenced by leakage of cerebrospinal fluid into the nasal cavity, and may be followed from the nasal cavity to the brain.
Blows to the head can also shear off the olfactory nerves that pass though the ethmoid bone and cause anosmia, an irreversible loss of the sense of smell and a great reduction in the sense of taste (most of which depends on smell). This not only deprives life of some of its pleasures, but can also be dangerous, as when a person fails to smell smoke, gas, or spoiled food.
Role in magnetoception
Some birds and other migratory animals have deposits of biological magnetite in their ethmoid bones which allow them to sense the direction of the Earth's magnetic field. Humans have a similar magnetite deposit, but it is believed to be vestigial.
