Ethmoid bone

Bone: Ethmoid bone
Illu cranial bones2.jpg
Cranial bones
Orbital bones.png
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. The ethmoid has three parts: the cribriform plate, the ethmodial labyrinth, and the perpendicular plate

Contents

Articulations

The ethmoid articulates with fifteen bones:

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.

The porous, fragile nature of the ethmoid bone makes it particularly susceptible to fractures. The ethmoid is usually fractured from an upward force to the nose. This could occur by hitting the dashboard in a car crash or landing on the ground after a fall. The ethmoid fracture can produce bone fragments that penetrate the cribriform plate. This trauma can lead to a leak of cerebral spinal fluid into the nasal cavity. These openings allow for opportunistic bacteria in the nasal cavity to enter the sterile environment of the central nervous system (CNS). The CNS is usually protected by the blood brain barrier, but holes in the cribriform plate allow bacteria to surpass the barrier. The blood brain barrier makes it extremely difficult to treat such infections because only certain drugs can cross in the CNS.

An ethmoid fracture can also sever the olfactory nerve. This injury results in anosmia, or the loss of smell. A reduction in the ability to taste is also a side effect because it is based so heavily on smell. This injury is not fatal.

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.[1]

Additional images

See also

References

  1. ^ Nature 301, 78 - 80 (06 January 1983); doi:10.1038/301078a0

2. Saladin, Kenneth S. "Anatomy and Physiology: the Unity of Form and Function" McGraw Hill, 5th ed. New York: 2010

3. Banks, Peter. "Fractures of the Facial Skeleton" Elsevier Health Sciences, 2001

External links

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.


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Look at other dictionaries:

  • Ethmoid bone — Ethmoid Eth moid, Ethmoidal Eth*moid al, a. [Gr. ? like a sieve; ? sieve + ? from: cf. F. ethmo[ i]de, ethmo[ i]dal.] (Anat.) (a) Like a sieve; cribriform. (b) Pertaining to, or in the region of, the ethmoid bone. [1913 Webster] {Ethmoid bone}… …   The Collaborative International Dictionary of English

  • Ethmoid bone — An irregularly shaped bone that provides the floor of the front part of the skull and the roof of the nose. The ethmoid bone consists of two masses of thin plates enclosing air cells and looks like a sieve. The word ethmoid comes from two Greek… …   Medical dictionary

  • ethmoid bone — noun one of the eight bones of the cranium; a small bone filled with air spaces that forms part of the eye sockets and the nasal cavity • Syn: ↑ethmoid • Hypernyms: ↑bone, ↑os • Part Holonyms: ↑cranium, ↑braincase, ↑ …   Useful english dictionary

  • ethmoid bone — a bone in the floor of the cranium that contributes to the nasal cavity and orbits. The part of the ethmoid forming the roof of the nasal cavity – the cribriform plate – is pierced with many small holes through which the olfactory nerves pass.… …   The new mediacal dictionary

  • ethmoid bone — noun The bone of the skull between the eyes and at the roof of the nose …   Wiktionary

  • Orbital lamina of ethmoid bone — Ethmoid bone from the right side. (Lamina papyracea visible at center left.) …   Wikipedia

  • Uncinate process of ethmoid bone — Infobox Bone Name = Uncinate process of ethmoid bone Latin = processus uncinatus ossis ethmoidalis GraySubject = 36 GrayPage = 155 Caption = Lateral wall of nasal cavity, showing ethmoid bone in position.(Unciate process of ethmoid labeled at… …   Wikipedia

  • Perpendicular plate of ethmoid bone — Infobox Bone Name = Perpendicular plate of ethmoid bone Latin = lamina perpendicularis ossis ethmoidalis GraySubject = 36 GrayPage = 154 Caption = Perpendicular plate of ethmoid. Shown by removing the right labyrinth. Caption2 = Ethmoid bone from …   Wikipedia

  • Кость Решетчатая (Ethmoid Bone, Cribriform Plate) — кость мо гового отдела черепа, которая входит в состав переднего отдела основания черепа и главным образом лицевого черепа, участвуя в образовании стенок глазниц и носовой полости. Решетчатая пластинка решетчатой кости (cribriform plate)… …   Медицинские термины

  • ethmoidal infundibulum of ethmoid bone — i. ethmoidale ossis ethmoidalis …   Medical dictionary

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