Ethmoid bone
From Free net encyclopedia
Template:Infobox Bone 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.
Contents |
Parts
The ethmoid bone consists of four parts:
- the horizontal Cribriform plate (lamina cribrosa), part of the cranial base
- the vertical Perpendicular plate (lamina perpendicularis), which is part of the nasal septum
- the two lateral masses or labyrinths.
Articulations
The ethmoid articulates with fifteen bones: four of the cranium—the frontal, the sphenoid, and the two sphenoidal conchæ; and eleven of the face—the two nasals, two maxillæ, two lacrimals, two palatines, two inferior nasal conchæ, and the vomer.
Injuries
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 follwoed 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.
See also
fr:Os éthmoïde it:Osso etmoide nl:Zeefbeen ja:篩骨 pl:Kość sitowa