Anatomy of the Ear

by Nicole Whitworth on June 4, 2012

Anatomy and Physiology is the single most important topic to master if you want to succeed in nursing school.  If you’ve never been a fan of anatomy and physiology, then you’re in the right place! I believe in breaking through all the confusing technical jargon to get right to the point of what’s most important to remember.  What does that mean for you?  Clear, understandable explanations that give you that “lightbulb” moment you’ve been hoping for.

Anatomy of the Ear

Click to enlarge this image

Here’s an overview of what you should be familiar with when it comes to the A&P of the ear:

External Ear

Auricle:  “Auricle” is the most recognizable part of your ear.  You’ll also see it referred to as the “pinna.” The unique shape actually helps funnel sound waves into the auditory canal!

Earlobe:  Still the most popular location for a piercing!

(External) Auditory Canal: This is the official name for those holes in the sides of your head!  It’s about an inch long in adults, and ends at the eardrum. The Auditory Canal also contains the glands that produce ceruman (ear wax).

Tympanic Membrane (aka Ear Drum): The ear drum is the very thin membrane that acts as a “wall” completely separating the external ear from the middle ear.  Which means that your mom was right…if you stick that q-tip too far into your ear, you really CAN puncture your ear drum!  The ear drum is the first step in the chain reaction that turns sound waves into sound.

Middle Ear

Tympanic Cavity: This is the name of the physical space that contains the all the structures of the middle ear.

Ossicles:  These are the 3 smallest bones in the body.  They pick up on ear drum vibrations and pass them through to the middle ear.

  • Malleus (aka Hammer):  The first little bone in the series.  It is attached to the center of the ear drum on one end, and to the Incus on the other end.  It is commonly referred to as the “Hammer” bone because of the way it looks.  The name can help you remember:  Malleus -> Mallet -> Hammer.
  • Incus (aka Anvil):  The second little bone in the series.  It’s attached to the Malleus on one end, and the Stapes on the other.  Nicknamed the “Anvil” because that’s what it kind of looks like.
  • Stapes (aka Stirrup): The third and final little bone in the series.  It’s attached to the Incus on one end, and the Oval Window on the other end.  By now, it shouldn’t surprise you to discover that it’s also called the “Stirrup” because it sort of looks like…a stirrup.

Oval Window (aka Vestibular Window; not labeled in diagram): The Stapes covers up this little hole that marks the separation of the middle ear and the inner ear.  The sound vibrations that the ossicles are transporting move through here and into the cochlea.

Round Window (not labeled in diagram): This nifty little hole is covered by a thin membrane that is similar to the ear drum, but it has a very different function.  When the stapes vibrates against the oval window, it’s supposed to cause the fluid in the cochlea to start swishing around.  But since the cochlea is a stiff structure filled to the brim with fluid, there’s really no room for swishing…except that the membrane covering the round window stretches to accommodate the extra space needed for swishing.  Pretty cool design!

Inner Ear

Cochlea:  This is a very complex little organ that looks like a snail’s shell.  It’s filled with all kinds of stuff, including fluid, the Organ of Corti, cilia (aka tiny hairs), a couple membranes, and the Cochlear Nerve.  When the Stapes vibrates, it makes the fluid swish.  When the fluid swishes, it causes the cilia to move.  When the cilia move, the Organ of Corti notices and transfers that information to the Cochlear Nerve.  Then the Cochlear Nerve transfers that information to the brain for interpretation into sound.  Whew!  I could probably do a whole article just on the Cochlea!

Semi-circular Ducts: There are actually 3 of these:  the posterior canal, the horizontal (aka lateral) canal, and the superior (aka anterior) canal (isn’t it annoying how almost everything in anatomy seems to have at least 2 names?).  The body uses these 3 semi-circular canals to determine position and movement.

Cranial Nerve VIII (aka the Vestibular and Cochlear Nerves, aka Vestibulocochlear Nerve, aka Acoustic Nerve): Do you remember your mnemonic for the 12 cranial nerves?  Nerve #8 is in charge of balance and sound (it IS in the ear, after all).

Temporal Bone: No tricks here, the temporal bone is just a piece of your skull.  Review the

Bony Labrynth: A special name for the area within the temporal bone that is carved out specifically for the cochlea and semi-circular ducts to fit into.

Auditory Tube (aka Eustachian Tube): This canal connects the ear to the nose and throat cavity.  Does it now  makes sense why “Ear, Nose, and Throat” topics are usually all lumped together?  This little tube is usually closed, but can be opened when you do things like yawning or swallowing.  Go ahead, try it for yourself right now…nobody will think you look weird 

 

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{ 1 comment… read it below or add one }

Deogratias September 12, 2014 at 3:06 pm

Very cool. I have an old anatomy book I got from an Aunt with these types of imegas in it too. I’m a Nurse so they don’t bother me. I think the body is very cool to look at.

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