How the Ear Works

The ear is one of our five senses and is responsible for hearing and balance.  The ear consists of the outer ear, middle ear and inner ear.

The outer ear is that part of the ear that is visible and includes the ear lobe, pinna and external auditory canal. The pinna directs sound into the ear canal and serves as protection for the more delicate structures of the ear.

The middle ear is separated from the ear canal by the eardrum (tympanic membrane).  The eardrum is a thin membrane that moves in response to sound and transmits sound energy to the inner ear through the chain of 3 bones (ossicles).  The ossicles consist of the malleus (hammer), incus (anvil) and stapes (stirrup) and they are attached to the eardrum within the middle ear.  The stapes connects to the inner ear at the oval window.

The inner ear consists of the cochlea, which contains fluid filled tubes and hair cells.  As the stapes moves in and out of the oval window, it transmits sound energy to the fluid and subsequently to the hair cells.  This results in the vibrations being converted to nerve impulses that are transmitted to the brain so that the sound can be “heard.”

Another important structure of the ear is the eustachian tube.  It is a tube that connects the middle ear with the back of the nose.  The eustachian tube is responsible for equalizing air pressure so that the air pressure in the middle ear is the same as that in the atmosphere around us.  Blockage of the eustachian tube often requires medical intervention, especially in children.