Anatomy of the Ear

There are three parts of the ear that all work together to allow us to hear. These parts are called the outer, middle, and inner ears.

Outer Ear

The components of the Outer Ear are:

  • Pinna
  • Ear Canal

The job of the Pinna is to “trap” sound waves and funnel it into the ear canal.  There are many undulations and curves in the Pinna and each of those small sections help to funnel sound waves into the canal. The ear canal furthers this process by allowing sound waves to arrive at it’s next destination, the tympanic membrane, or eardrum. There are glands in the ear canal that produce cerumen, or earwax. The role of cerumen is to collect foreign objects, such as dust and dirt, in an attempt to not allow it into the canal. Everyone produces cerumen at different rates and it is not uncommon for one ear to accumulate cerumen quicker than the other.

Middle Ear

The components of the Middle Ear are:

  • Tympanic Membrane
  • Ossicles
  • Eustachian Tube

The job of the Tympanic Membrane, or eardrum, is to amplify sound waves. Once a sound wave hits the tympanic membrane, it is amplified by small vibrations of the eardrum. The ossicular chain is the connection of the ossicles (malleus “hammer”, incus “anvil”, and stapes “stirrup”). The malleus is attached to the tympanic membrane and moves simultaneously with the membrane. As the mallues moves, so to does the incus and stapes. As the stapes moves, it allows for fluid movement in the cochlea (inner ear).

The Eustachian Tube allows for normal middle ear pressure. It also helps to drain fluid from the middle ear cavity into the throat. If one end of the Eustachian Tube is closed when it should be open, this allows for a build-up of pressure behind the tympanic membrane.

Inner Ear

The components of the Inner Ear are:

  • Cochlea
  • Semicircular Canals
  • Auditory Nerve

The job of the cochlea is to convert sounds waves from mechanical energy to electrical energy on the auditory nerve. Once the footplate of the stapes moves, it sends the fluid in the cochlea into motion. This motion then triggers the stereocilia to create an electrical impulse on the auditory nerve. The auditory nerve then carries this message to the brain and is registered as a “sound”.

The semicircular canals help to regulate balance in the body. As a person moves, the three canals work in harmony to let the person know how they are moving in space. If one of the canals does not regulate motion properly, an imbalance occurs in the brain and the person becomes “dizzy”.