Anatomy Guide › Head & neck
Ethmoid Bone
The ethmoid bone is one of the skull's best-kept secrets. You cannot touch it from the outside — it sits deep between the two eye sockets, at the roof of the nasal cavity — yet it participates in the floor of the skull, the walls of both orbits, and the framework of the nose all at once. Its name comes from the Greek for 'sieve,' and one look explains why: its top plate, the cribriform plate, is perforated like a colander.
Those perforations are not a design flaw. Threads of the olfactory nerve pass through them, connecting scent receptors in the nasal lining directly to the brain. Every smell you have ever experienced traveled through the holes of the ethmoid bone. This is also why a severe head injury that fractures the cribriform plate can abolish the sense of smell, and in rare cases lets cerebrospinal fluid leak into the nose.
The rest of the bone is a labyrinth of thin-walled air cells — the ethmoid sinuses — and two scrolled projections called conchae that curl into the nasal cavity. The scrolls force incoming air into swirling paths, giving the moist lining more time to warm, humidify, and filter every breath. The ethmoid is so light and lacy that surgeons treat it with particular respect: it borders the eyes and the brain within millimeters.
In Anamo, the ethmoid is a satisfying expert-level answer. It touches the frontal bone, nasal bones, and vomer, so heat from guesses across the middle of the face converges on it — a classic case where anatomical adjacency knowledge beats guessing by surface landmarks.
- Named from the Greek for 'sieve' after its perforated cribriform plate
- Olfactory nerve fibers for smell pass through its perforations
- Contributes to the skull base, both eye sockets, and the nasal cavity
- Filled with air cells that form the ethmoid sinuses
Think you could find the ethmoid bone on a 3D model? Play Anamo and test yourself — every guess is color-coded by how close it lands to the mystery structure.