Bone: Ethmoid bone
Cranial bones
The seven bones which articulate to form the orbit. (Ethmoid is brown)
Latin	os ethmoidale
Gray's	subject #36 153
MeSH	Ethmoid+bone

The ethmoid bone (from Greek ethmos, "sieve") 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 one of the bones that makes up the orbit of the eye.

Contents 1 Articulations 2 Injuries 3 Role in magnetoception 4 Additional images 5 See also 6 References 7 External links

[edit] Articulations

The ethmoid articulates with fifteen bones:

• four of the neurocranium—the frontal, and the sphenoid (at the sphenoidal body and at the sphenoidal conchae).
• eleven of the viscerocranium—, two Nasal bones, two maxillae, two lacrimals, two palatines, two inferior nasal conchae, and the vomer

[edit] Injuries

Fracture of the lamina papyracea, the lateral plate of the ethmoid labyrinth bone, permits communication between the nasal cavity and the ipsilateral orbit through the inferomedial orbital wall, resulting in orbital emphysema. Increased pressure within the nasal cavity, as seen during sneezing, for example, leads to temporary exophthalmos.

[edit] 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.^{[citation needed]}

[edit] Additional images

Ethmoid bone from above.	Perpendicular plate of ethmoid.	Ethmoid bone (frontal view).	Ethmoid bone from the right side.
Sphenoid bone visible center right.	Side view of the skull.	The skull from the front.	Medial wall of left orbit.
Base of the skull. Upper surface.	Medial wall of left nasal fossa.	Roof, floor, and lateral wall of left nasal cavity.	Lateral wall of nasal cavity, showing ethmoid bone in position.
Ethmoid bone

[edit] See also

• Ossification of ethmoid
• Bone terminology
• Terms for anatomical location

[edit] References

[edit] External links

• http://www.theregister.com/2006/11/17/the_odd_body_nose_compass/
• Roche Lexicon - illustrated navigator, at Elsevier 34256.000-1

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

v • d • e The Bones which form the Orbit Frontal bone • Zygomatic bone • Maxillary bone • Sphenoid bone • Ethmoid bone • Palatine bone • Lacrimal bone

v • d • e Bones of head and neck: the neurocranium of the skull (TA A02.1.01-07, GA 2.129-155) Occipital Squama external (Inion/External occipital protuberance, Nuchal lines) · planes (Occipital, Nuchal) · internal (Cruciform eminence, Internal occipital protuberance, Sagittal sulcus, Internal occipital crest) Lateral parts Condyle (Condyloid fossa, Condylar canal) · Hypoglossal canal · jugular (Jugular process, Jugular tubercle) Basilar part Pharyngeal tubercle Other Foramen magnum (Basion, Opisthion) Parietal Parietal eminence · Temporal line · Parietal foramen Frontal Squama Frontal suture · Frontal eminence · external (Superciliary arches, Glabella) · foramina (Supraorbital, Cecum) · Zygomatic process · internal (Sagittal sulcus, Frontal crest) Orbital part Ethmoidal notch · Lacrimal fossa · Trochlear fovea · Frontal sinus · Frontonasal duct Temporal Squama Articular tubercle · Suprameatal triangle · Mandibular fossa · Petrotympanic fissure · Zygomatic process Mastoid part Mastoid foramen · Mastoid process (Mastoid cells) · Mastoid notch · Occipital groove · Sigmoid sulcus · Mastoid antrum (Aditus) Petrous part Carotid canal · Facial canal (Hiatus) · Internal auditory meatus · Cochlear aqueduct · Stylomastoid foramen fossae (Subarcuate fossa, Jugular fossa) · canaliculi (Inferior tympanic, Mastoid) · Styloid process · Petrosquamous suture (note: ossicles in petrous part, but not part of temporal bone) Tympanic part Suprameatal spine Sphenoid Surfaces Superior surface: Sella turcica (Dorsum sellae, Tuberculum sellae, Hypophysial fossa, Posterior clinoid processes) · Ethmoidal spine · Chiasmatic groove · Middle clinoid process · Petrosal process · Clivus Lateral surface: Carotid groove · Sphenoidal lingula Anterior surface: Sphenoidal sinuses Great wings foramina (Rotundum, Ovale, Vesalii, Spinosum) · Spine · Infratemporal crest · Sulcus for auditory tube Small wings Superior orbital fissure · Anterior clinoid process · Optic canal Pterygoid processes fossae (Pterygoid, Scaphoid) · pterygoid plates (Lateral, Medial) · Pterygoid canal · Hamulus Other Body · Sphenoidal conchae Ethmoid Plates Cribriform plate (Crista galli, Olfactory foramina) · Perpendicular plate Surfaces Lateral surface Orbital lamina · Uncinate process Medial surface Superior nasal concha · Superior meatus · Middle nasal concha · Middle meatus Labyrinth Ethmoid sinus · ethmoidal foramina (Posterior, Anterior)