from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A small bone, especially one of the three bones of the middle ear.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A small bone (or bony structure), especially one of the three of the middle ear.
- n. Bone-like joint or plate, especially:
from the GNU version of the Collaborative International Dictionary of English
- n. A little bone.
- n. One of numerous small calcareous structures forming the skeleton of certain echinoderms, as the starfishes.
from The Century Dictionary and Cyclopedia
- n. A small bone or bonelet.
- n. A small hard nodule of chitin or some substance resembling bone.
- n. Also ossicule, ossiculum.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a small bone; especially one in the middle ear
There's little point discussing the minutiae of ossicle evolution if you reject that reptiles and mammals share a common ancestor.
If the eardrum is no longer physically connected to the inner ear, i.e. loss of a single ossicle, the impedance matching effectively reduces to zero (in fact "poor impedance matching" is just an oxymoron), but hearing does not require all parts of the system.
Every reptile, living or fossil, however, has at least four bones in the lower jaw and only one auditory ossicle, the stapes… There are no transitional fossil forms showing, for instance, three or two jawbones, or two ear bones.
Though some would debate your right to ears if you keep your iPod volume maxed at an ossicle-wobbling level, an owner of Apple's popular Lilliputian jukebox has filed a lawsuit against the computer maker, claiming the device can cause hearing loss in people who use it.
Among von Békésy's important contributions to our knowledge of sound transmission in the middle ear should be mentioned the elucidation of the vibration patterns of the eardrum and of the interplay of the ossicle movements.
The footplate of the stirrup which serves as the innermost link of the ossicle chain is movably mounted in the opening of the oval window of the inner ear which faces the middle ear.
Within the airfilled middle ear the vibrations are transmitted via a subtle system of levers, the ossicle chain, to the fluid of the inner ear, the cochlea.
If the tiny muscles attached to them are damaged, or if the nerves leading to those muscles are, the ossicle movements become somewhat erratic.
The second ossicle which receives the hammer blows is the incus ( "anvil" L).
Because in doing so it strikes again and again on the second bone, this first ossicle is called the matteus (mal'ee-us; "hammer" L).