Parts of the Auditory System

"When we do a hearing assessment there are three parts of the auditory system that we're primarily evaluating. The first part is the outer ear, so we examine the external part of the ear which we refer to as the pinna and the ear canal. We use a device called an autoscope, which is essentially a light with a magnifying lens to look into the ear canal and we can see as far as the ear drum. The second part of the assessment evaluates the middle ear. In the middle ear, that's the space behind the ear drum, in a normal, healthy ear it's an air filled space. In there we have three little bones that are referred to as the asocales. The middle ear space it functions as a impedance matching device so it takes sound that's being transmitted in the ear, which hits the ear drum and causes the ear drum to vibrate. The bones, the vibration of the ear drum then sets those bones into motion and the function of that whole middle ear system is to transfer the sound energy from air to th inner ear which is the fluid filled space. So the middle ear is a mechanical system.The inner ear is the part of the assessment we're evaluating when we're doing the pure tone testing or the part of the assessment where we're determining how soft sounds at specific frequencies need to be for someone to hear them. That's where we're evaluating what's known as the inner ear or the cochlea. The cochlea is a snail shaped boney device that is fluid filled and contains all of the sensory nerves that detect sound."