Library · Anatomy
Ear ossicles
Make it clearer
The middle ear holds three tiny bones, the ossicles: the malleus, the incus and the stapes. They are linked one after another, and their job is to carry vibrations from the eardrum to the inner ear, amplifying them along the way.
That amplification is not a luxury. On one side of the chain there is air and on the other there is fluid, and pushing fluid takes far more effort than pushing air. The chain bridges that gap: it works as an impedance matcher, which is the technical way of saying that it couples two very different media so that energy is not lost.
It does this in two ways. The eardrum and the oval window, the doorway into the inner ear, are not the same size, and the ossicles also add leverage: they act as a lever between two surfaces of very different size. That raises the pressure by about twenty to thirty decibels.
There is a brake as well: the stapedius muscle contracts, stiffens the chain and lets less sound through, especially the low tones.
In brief
The three middle ear ossicles, the malleus, incus and stapes, carry and amplify vibrations from the eardrum to the inner ear.
The chain acts as an impedance matcher between middle ear air and inner ear fluid.
The area difference between the eardrum and the oval window, plus the lever action, raises pressure by about 20 to 30 decibels.
A lever between two surfaces of very different size.
When the stapedius muscle contracts, it stiffens the chain and lets less sound through, especially low tones.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingAnatomy, Head and Neck: Middle Ear, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated