Have You Heard?
Published 12:00 am Friday, April 6, 2012
Last month we discussed the amazing function of the Outer Ear. We learned that the visible portion, the pinna, does more than provide us with a place to hang our glasses. The pinna scoops sound sending it down the ear canal causing the eardrum (tympanic membrane) to vibrate. The ear canal itself naturally amplifies the higher frequencies so important for speech understanding.
This month we will marvel at the magic of the Middle Ear. The middle ear actually starts where the outer ear left off. The tympanic membrane actually is composed of three layers so the middle ear starts with the most interior layer. The middle ear is an air-filled cavity.
Did you know that the 3 smallest bones in our body are in the middle ear? They are the hammer (malleus), anvil (incus) and stirrup (stapes). They are connected to each other with the malleus attached to the 3rd layer of the eardrum. So as the eardrum vibrates, the bones start moving. The stirrup is also connected to a membrane called the round window so as the stirrup moves, so does the round window. The round window separates the middle ear from the inner ear…but that is the story for next month.
Like the outer ear, the middle ear also has natural amplifying characteristics. Since the surface area of the tympanic membrane is much larger than that of the round window there is greater force put on the round window as it vibrates…NEED ANALOGY
Our Eustachian Tube is also in the middle ear. You are familiar with its function if you have been in an airplane or while driving in the mountains. The Eustachian tube is responsible for equalizing the pressure inside and outside of our head. So when your ears pop, you have been equalized.
Typically problems in the middle ear can be corrected medically or surgically. Fluid in the middle ear may require tubes placed in the eardrum to help with ventilation. Sometimes the bones do not move well (otosclerosis) and must be replaced with prosthesis. Sometimes the bones become disconnected from a head injury and must be reconnected. Or our Eustachian tube may not function properly due to sinus problems.
So if you are noticing hearing difficulty, the way to determine if your problem is a result of a middle ear problem is with an audiometric evaluation. Our testing tools can determine where your problem lies.
For more information on hearing loss, hearing aids or to schedule an appointment, please contact our office at Hearing Lifestyles, 704-633-0023.
Dr. Lorin S Oden is a Board Certified Audiologist at Hearing Lifestyles, LLC located at 464 Jake Alexander Blvd., West, Salisbury, NC 28147. Call 704-633-0023 or visit their website at www.hearinglifestyles.com