Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Middle Ear shopping experience:
1. Compare - without doubt the biggest advantage that the Middle Ear offers shoppers today is the ability to compare thousands of Middle Ear at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Middle Ear? Wrong! If the Middle Ear is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Middle Ear then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Middle Ear? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Middle Ear and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Middle Ear wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Middle Ear then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Middle Ear site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Middle Ear, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Middle Ear, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
{{Infobox Anatomy | Name = {{PAGENAME--> |
Latin = auris media |
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Map = Middle ear map |
MapPos = None|
MapCaption = Bones and muscles in the tympanic cavity in the middle ear |
Precursor = |
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Artery = |
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MeshName = Middle+ear |
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-->The
middle ear is the portion of the ear internal to the eardrum, and external to the
oval window of the
cochlea. The mammalian middle ear contains three
ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the
inner ear. The hollow space of the middle ear has also been called the tympanic cavity, or
cavum tympani. The eustachian tube joins the tympanic cavity with the nasal cavity (
nasopharynx), allowing pressure to equalize between the inner ear and throat.
The primary function of the middle ear is to efficiently transfer acoustic energy from compression waves in air to fluid–membrane waves within the cochlea.
Sound transfer
Ordinarily, when sound waves in air strike liquid, most of the energy is reflected off the surface of the liquid. The middle ear allows the impedance matching of sound traveling in air to acoustic waves traveling in a system of fluids and membranes in the inner ear. This system should not be confused, however, with the propagation of sound as compression waves in a liquid.
The middle ear couples sound from air to the fluid via the oval window, using the principle of "mechanical advantage" in the form of the "hydraulic principle" and the "lever principle". The vibratory portion of the tympanic membrane is many times the surface area of the footplate of the stapes; furthermore, the shape of the articulated ossicular chain is like a lever, the long arm being the long process of the malleus, and the body of the incus being the fulcrum and the short arm being the lenticular process of the incus. The collected pressure of sound vibration that strikes the tympanic membrane is therefore concentrated down to this much smaller area of the footplate, increasing the force but reducing the velocity and displacement, and thereby coupling the acoustic energy.
The middle ear is able to dampen sound conduction substantially when faced with very loud sound, by noise-induced reflex contraction of the middle-ear muscles.
Ossicles
The middle ear contains three tiny bones known as the
ossicles:
malleus,
incus, and
stapes. The ossicles were given their Latin names for their distinctive shapes; they are also referred to as the
hammer,
anvil, and
stirrup, respectively. The ossicles directly couple sound energy from the ear drum to the
oval window of the cochlea. While the stapes is present in all tetrapods, the
malleus and
incus evolved from lower and upper jaw bones present reptiles. See
Evolution of mammalian auditory ossicles.
The ossicles are classically supposed to mechanically convert the vibrations of the eardrum, into amplified pressure waves in the fluid of the
cochlea (or
inner ear) with a lever arm factor of 1.3. Since the area of the eardrum is about 17 fold larger than that of the
oval window, the sound pressure is concentrated, leading to a pressure gain of at least 22. The eardrum is fused to the malleus, which connects to the incus, which in turn connects to the stapes. Vibrations of the stapes footplate introduce pressure waves in the inner ear. There is a steadily increasing body of evidence which shows that the lever arm ratio is actually variable, depending on frequency. Between 0.1 and 1 kHz it is approximately 2, it then rises to around 5 at 2 kHz and then falls off steadily above this frequency.Koike et al.: Modeling of the human middle ear J. Acoust. Soc. Am., Vol. 111, No. 3, March 2002 The measurement of this lever arm ratio is also somewhat complicated by the fact that the ratio is generally given in relation to the tip of the
malleus (also known as the
umbo) and the level of the middle of the stapes. The eardrum is actually attached to the malleus handle over about a 1cm distance. In addition the eardrum itself moves in a very chaotic fashion at frequencies >3 kHz. The linear attachment of the
eardrum to the malleus actually smooths out this chaotic motion and allows the ear to respond linearly over a wider frequency range than a point attachment. The auditory ossicles can also reduce sound pressure (the inner ear is very sensitive to overstimulation), by uncoupling each other through particular muscles.
The middle ear efficiency peaks at a frequency of around 1 kHz. The combined transfer function of the outer ear and middle ear gives humans a peak sensitivity to frequencies between 1 kHz and 3 kHz.
Muscles
The movement of the ossicles may be stiffened by two muscles, the stapedius and tensor tympani, which are under the control of the
facial nerve and trigeminal nerve, respectively. These muscles contract in response to loud sounds, thereby reducing the transmission of sound to the inner ear. This is called the
acoustic reflex.
Nerves
Of surgical importance are two branches of the
facial nerve which also pass through the middle ear space. These are the horizontal and
chorda tympani branches of the facial nerve. Damage to the horizontal branch during surgery can lead to partial, unilateral facial paralysis.
Comparative anatomy
Mammals are unique in having three ear bones. The incus and stapes have evolved from bones of the jaw, and allow finer detection of sound.
Some mammals, such as the
cat, have an enlarged middle ear encased in a thin, bulbous bone; this structure is known as a bulla.
Disorders of the middle ear
The middle ear is hollow. If the animal moves to a high-altitude environment, or dives into the water, there will be a pressure difference between the middle ear and the outside environment. This pressure will pose a risk of bursting or otherwise damaging the tympanum if it is not relieved. This is one of the functions of the Eustachian tubes which connect the middle ear to the
nasopharynx. The Eustachian tubes are normally pinched off at the nose end, to prevent being clogged with mucus, but they may be opened by lowering and protruding the jaw; this is why
yawning helps relieve the pressure felt in the ears when on board an aircraft.
Otitis media is an inflammation of the middle ear.
Additional images
Image:Gray919.png
External links
- Promenade Around the Cochlea - Middle ear at iurc.montp.inserm.fr
References
{{Infobox Anatomy | Name = {{PAGENAME--> |
Latin = auris media |
GraySubject = 230 |
GrayPage = 1037 |
Image = |
Caption = |
Image2 = |
Caption2 = |
Map = Middle ear map |
MapPos = None|
MapCaption = Bones and muscles in the tympanic cavity in the middle ear |
Precursor = |
System = |
Artery = |
Vein = |
Nerve = [glossopharyngeal nerve |
Lymph = |
MeshName = Middle+ear |
MeshNumber = A09.246.397 |
DorlandsPre = a_73 |
DorlandsSuf = 12169777 |
-->The
middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three
ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has also been called the
tympanic cavity, or
cavum tympani. The
eustachian tube joins the tympanic cavity with the nasal cavity (
nasopharynx), allowing pressure to equalize between the inner ear and throat.
The primary function of the middle ear is to efficiently transfer acoustic energy from compression waves in air to fluid–membrane waves within the
cochlea.
Sound transfer
Ordinarily, when sound waves in air strike liquid, most of the energy is reflected off the surface of the liquid. The middle ear allows the impedance matching of sound traveling in air to acoustic waves traveling in a system of fluids and membranes in the inner ear. This system should not be confused, however, with the propagation of sound as compression waves in a liquid.
The middle ear couples sound from air to the fluid via the oval window, using the principle of "mechanical advantage" in the form of the "hydraulic principle" and the "lever principle". The vibratory portion of the tympanic membrane is many times the surface area of the footplate of the stapes; furthermore, the shape of the articulated ossicular chain is like a lever, the long arm being the long process of the malleus, and the body of the incus being the fulcrum and the short arm being the lenticular process of the incus. The collected pressure of sound vibration that strikes the tympanic membrane is therefore concentrated down to this much smaller area of the footplate, increasing the force but reducing the velocity and displacement, and thereby coupling the acoustic energy.
The middle ear is able to dampen sound conduction substantially when faced with very loud sound, by noise-induced reflex contraction of the middle-ear muscles.
Ossicles
The middle ear contains three tiny bones known as the
ossicles:
malleus,
incus, and
stapes. The ossicles were given their Latin names for their distinctive shapes; they are also referred to as the
hammer,
anvil, and
stirrup, respectively. The ossicles directly couple sound energy from the ear drum to the
oval window of the cochlea. While the stapes is present in all tetrapods, the malleus and incus evolved from lower and upper jaw bones present reptiles. See Evolution of mammalian auditory ossicles.
The ossicles are classically supposed to mechanically convert the vibrations of the
eardrum, into amplified pressure waves in the fluid of the cochlea (or
inner ear) with a lever arm factor of 1.3. Since the area of the eardrum is about 17 fold larger than that of the
oval window, the sound pressure is concentrated, leading to a pressure gain of at least 22. The eardrum is fused to the malleus, which connects to the incus, which in turn connects to the stapes. Vibrations of the stapes footplate introduce pressure waves in the
inner ear. There is a steadily increasing body of evidence which shows that the lever arm ratio is actually variable, depending on frequency. Between 0.1 and 1 kHz it is approximately 2, it then rises to around 5 at 2 kHz and then falls off steadily above this frequency.Koike et al.: Modeling of the human middle ear J. Acoust. Soc. Am., Vol. 111, No. 3, March 2002 The measurement of this lever arm ratio is also somewhat complicated by the fact that the ratio is generally given in relation to the tip of the
malleus (also known as the
umbo) and the level of the middle of the stapes. The eardrum is actually attached to the
malleus handle over about a 1cm distance. In addition the
eardrum itself moves in a very chaotic fashion at frequencies >3 kHz. The linear attachment of the eardrum to the
malleus actually smooths out this chaotic motion and allows the ear to respond linearly over a wider frequency range than a point attachment. The auditory ossicles can also reduce sound pressure (the inner ear is very sensitive to overstimulation), by uncoupling each other through particular muscles.
The middle ear efficiency peaks at a frequency of around 1 kHz. The combined transfer function of the outer ear and middle ear gives humans a peak sensitivity to frequencies between 1 kHz and 3 kHz.
Muscles
The movement of the ossicles may be stiffened by two muscles, the stapedius and tensor tympani, which are under the control of the
facial nerve and trigeminal nerve, respectively. These muscles contract in response to loud sounds, thereby reducing the transmission of sound to the inner ear. This is called the
acoustic reflex.
Nerves
Of surgical importance are two branches of the facial nerve which also pass through the middle ear space. These are the horizontal and
chorda tympani branches of the facial nerve. Damage to the horizontal branch during surgery can lead to partial, unilateral facial paralysis.
Comparative anatomy
Mammals are unique in having three ear bones. The incus and stapes have evolved from bones of the jaw, and allow finer detection of sound.
Some mammals, such as the cat, have an enlarged middle ear encased in a thin, bulbous bone; this structure is known as a bulla.
Disorders of the middle ear
The middle ear is hollow. If the animal moves to a high-altitude environment, or dives into the water, there will be a pressure difference between the middle ear and the outside environment. This pressure will pose a risk of bursting or otherwise damaging the tympanum if it is not relieved. This is one of the functions of the
Eustachian tubes which connect the middle ear to the nasopharynx. The Eustachian tubes are normally pinched off at the nose end, to prevent being clogged with mucus, but they may be opened by lowering and protruding the jaw; this is why yawning helps relieve the pressure felt in the ears when on board an aircraft.
Otitis media is an inflammation of the middle ear.
Additional images
Image:Gray919.png
External links
- Promenade Around the Cochlea - Middle ear at iurc.montp.inserm.fr
References
Inflammation of the middle ear (otitis media)
Inflammation of the middle ear is an infection caused by a germ (bacterium). It is very common among children. The middle ear is an air-filled hollow between the eardrum and the ...
Middle ear - Wikipedia, the free encyclopedia
The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple ...
Medinfo: Middle ear infection (Otitis media)
Easy to understand information for patients on middle ear infection (otitis media). Written by a UK general practitioner.
TYMPANOPLASTY - MIDDLE EAR REPAIR
TYMPANOPLASTY - MIDDLE EAR REPAIR . Information about TYMPANOPLASTY - MIDDLE EAR REPAIR from Surgery Door's Medical Conditions Section
Outer and middle ear problems
21 January 2006 The Pharmaceutical Journal (Vol 276) 83 www.pjonline.com For personal use only. Not to be reproduced without permission of the editor (permissions@pharmj.org.uk ...
RefHelp - Middle Ear Effusion (Glue Ear)
An Official website of NHS Scotland (National Health Service for Scotland). ... MIDDLE EAR EFFUSION (GLUE EAR) Middle ear effusion (glue ear) in children is probably the commonest ...
Middle Ear Infections
Ear infections are common among kids and, often, painful. Find out what causes them and how they're treated. ... Next to the common cold, ear infections are the most commonly ...
Glue ear Introduction - Health encyclopaedia - NHS Direct
Build up of fluid in the middle ear ... Glue ear is a condition which causes fluid to build up in the middle ear.
Otitis media Introduction - Health encyclopaedia - NHS Direct
Inflammation of the middle ear ... Otitis media is a build-up of fluid in the middle ear, the space between the eardrum and the inner ear.
Otitis media - glue ear is an infection of the middle ear
Bupa health factsheet - otitis media (glue ear) mainly affects young children and is caused by blockage of the eustachian tube
