The Middle Ear

Part 1 of study guide

Tympanic membrane

Pars Tensa, Pars Flaccida

Otoscopy, what is it?

A medical procedure using a magnifying tool called an otoscope with a light to look inside your ear canal and exam eardrum

Middle ear spaces

Tympanic Cavity / Tympanum

Epitympanic Recess (aka the attic)

Mastoid Antrum

Ossicles

Malleus, IncusStapes (connected to the oval window)

• Smallest bone in the human body, so cute…. So much relies on this little guy!)

Middle Ear Muscle: Stapedius Muscle

• (contracts in response to loud sounds and before we talk)

  • Innervated by the 7th cranial nerve (facial nerve)

Middle Ear Muscle: Tensor Tympani Muscle

• (Helps open the eustachian tube and helps us not hear ourselves when we swallow food)

Eustachain Tube: Who is this creature and  what does it do!

A narrow tunnel-like passageway thats made of bone and cartilage. Connects from your middle ear to the back of your nose and upper throat. It equalizes ari pressure, frains fluid, and protects the ear from germs, viruses, and loud noises coming from your nose and throat

Eustachain Tube: Why does this not work as well in infants and young children?

Children have a much shorter, narrower, and much more horizontal than adults, which the angle prevents from fluid being drained, It also makes it easier for things to flow backward into the middle ear. Their cartilage is also more soft and flexible, less stiff

Middle Ear Transformer, There are three mechanisms that add that energy, back, and by energy in this case we are talking about an increase in pressure.  In the air, and also through the middle ear system, it is all about level

• Area Ratio Mechanism  (+25 dB)

• Ossicular Lever Mechanism (+6 dB)

• Curved Membrane Mechanism (+2 dB)

• Add those all together and we get an additional 33 dB of extra sound just from the vibrations traveling through the middle ear system

• Lets us here as well as we can for humans