10 - cochlea

The cochlea is the auditory portion of the inner ear. Its core component is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating fluid chambers in the coiled tapered tube of the cochlea.

The name is from the Latin for snail, which is from the Greek kokhlias "snail, screw," from kokhlos "spiral shell,"(etymology) in reference to its coiled shape; the cochlea is coiled in most mammals, monotremes being the exceptions.

Anatomy

Structural diagram of the cochlea showing how fluid pushed in at the oval window moves, deflects the cochlear partition, and bulges back out at the round window.

Structures

The cochlea is a spiralled, hollow, conical chamber of bone. Its structures include:

• the scala vestibuli (containing perilymph), which lies superior to the cochlear duct and abuts the oval window.
• the scala tympani (containing perilymph), which lies inferior to the scala media and terminates at the round window.
• the scala media (containing endolymph), which is the membranous cochlear duct containing the organ of Corti.
• the helicotrema is the location where the scala tympani and the scala vestibuli merge
• Reissner's membrane separates the scala vestibuli from the scala media.
• The basilar membrane, a main structural element that determines the mechanical wave propagation properties of the cochlear partition, separates the scala media from the scala tympani.
• The Organ of Corti is the sensory epithelium, a cellular layer on the basilar membrane, powered by the potential difference between the perilymph and the endolymph. It is lined with hair cells—sensory cells topped with hair-like structures called stereocilia.

Function

In brief: the cochlea is filled with a watery liquid, which moves in response to the vibrations coming from the middle ear via the oval window. As the fluid moves, thousands of "hair cells" are set in motion, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells. These primary auditory neurons transform the signals into electrical impulses known as action potentials, which travel along the auditory nerve to structures in the brainstem for further processing.

The stapes of the middle ear transmits to the fenestra ovalis (oval window) on the outside of the cochlea, which vibrates the perilymph (fluid) in the scala vestibuli (upper chamber of the cochlea).

This motion of perilymph in turn vibrates the endolymph in the scala media, the perilymph in the scala tympani, the basilar membrane, and organ of Corti, thus causing movements of the hair bundles of the hair cells, acoustic sensor cells that convert vibration into electrical potentials. The hair cells in the organ of Corti are tuned to certain sound frequencies^[1], being responsive to high frequencies near the oval window and to low frequencies near the apex of the cochlea.

The hair cells are arranged in four rows in the organ of Corti along the entire length of the cochlear coil. Three rows consist of outer hair cells (OHCs) and one row consists of inner hair cells (IHCs). The inner hair cells provide the main neural output of the cochlea. The outer hair cells, instead, mainly receive neural input from the brain, which influences their motility as part of the cochlea’s mechanical pre-amplifier. The input to the OHC is from the olivary body via the medial olivocochlear bundle.

For very low frequencies (below 20Hz), the pressure waves propagate along the complete route of the cochlea - up scala vestibuli, around helicotrema and down scala tympani to the round window. Frequencies this low do not activate the organ of Corti and are below the threshold for hearing. Higher frequencies do not propagate to the helicotrema but are transmitted through the endolymph in the cochlear duct to the perilymph in the scala tympani.

A very strong movement of the endolymph due to very loud noise may cause hair cells to die. This is a common cause of partial hearing loss and is the reason why users of firearms or heavy machinery should wear earmuffs or earplugs.

Detailed anatomy

The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue. This coiled tube is divided through most of its length by a membrane partition. Two fluid-filled spaces (scalae) are formed by this dividing membrane.

The fluid in both is called perilymph: a clear solution of electrolytes and proteins. The two scalae (fluid-filled chambers) communicate with each other through an opening at the top (apex) of the cochlea called the helicotrema, a common space that is the one part of the cochlea that lacks the lengthwise dividing membrane.

At the base of the cochlea each scala ends in a membrane that faces the middle ear cavity. The scala vestibuli ends at the oval window, where the footplate of the stapes sits. The footplate rocks when the ear drum moves the ossicular chain; sending the perilymph rippling with the motion, the waves moving away from footplate and towards helicotrema. Those fluid waves then continue in the perilymph of the scala tympani. The scala tympani ends at the round window, which bulges out when the waves reach it -providing pressure relief. This one-way movement of waves from oval window to round window occurs because the middle ear directs sound to the oval window, but shields the round window from being struck by sound waves from the external ear. It is important, because waves coming from both directions, from the round and oval window would cancel each other out. In fact, when the middle ear is damaged such that there is no tympanic membrane or ossicular chain, and the round window is oriented outward rather than set under a bit of a ledge in the round window niche, there is a maximal conductive hearing loss of about 60 dB.

The lengthwise partition that divides most of the cochlea is itself a fluid-filled tube, the third scalae. This central column is called the scala media or cochlear duct. Its fluid, endolymph, also contains electrolytes and proteins, but is chemically quite different from perilymph. Whereas the perilymph is rich in sodium salts, the endolymph is rich in potassium salts.

The cochlear duct is supported on three sides by a rich bed of capillaries and secretory cells (the stria vascularis), a layer of simple squamous epithelial cells (Reissner's membrane), and the basilar membrane, on which rests the receptor organ for hearing - the organ of Corti. The cochlear duct is almost as complex on its own as the ear itself.

The ear is a very active organ. Not only does the cochlea "receive" sound, it generates it. Some of the hair cells of the cochlear duct can change their shape enough to move the basilar membrane and produce sound. This process is important in fine tuning the ability of the cochlea to accurately detect differences in incoming acoustic information. The sound produced by the inner ear is called an otoacoustic emission (OAE), and can be recorded by a microphone in the ear canal. Otoacoustic emissions are important is some types of tests for hearing impairment.

Comparative physiology

The coiled form of cochlea is unique to mammals. In birds and in other non-mammalian vertebrates the compartment containing the sensory cells for hearing is occasionally also called “cochlea”, although it is not coiled up. Instead it forms a blind-ended tube, also called the cochlear duct. This difference apparently evolved in parallel with the differences in frequency range of hearing and in frequency resolution between mammals and non-mammalian vertebrates. Most bird species do not hear above 4–5 kHz, the currently known maximum being ~ 11 kHz in the barn owl. Some marine mammals hear up to 200 kHz. The superior frequency resolution in mammals is due to their unique mechanism of pre-amplification of sound by active cell-body vibrations of outer hair cells. A long coiled compartment, rather than a short and straight one, provides more space for frequency dispersion and is therefore better adapted to the highly derived functions in mammalian hearing.^[2]

As the study of the cochlea should fundamentally be focused upon the level of hair cells, it is important to note the anatomical and physiological differences between the hair cells of various species. In birds, for instance, instead of outer and inner hair cells, there are tall and short hair cells. There are several similarities of note in regard to this comparative data. For one, the tall hair cell is very similar in function to that of the inner hair cell and the short hair cell is very similar in function to that of the outer hair cell. One unavoidable difference, however, is that while all hair cells are attached to a tectorial membrane in birds, only the outer hair cells are attached to the tectorial membrane in mammals.

References

1. ^ Tasaki I. Nerve impulses in individual auditory nerve fibers of guinea pig. J Neurophysiol. 17(2): 97-122, 1954
2. ^ Vater M, Meng J, Fox RC. Hearing organ evolution and specialization: Early and later mammals. In: GA Manley, AN Popper, RR Fay (Eds). Evolution of the Vertebrate Auditory System, Springer-Verlag, New York 2004, pp 256–288.

9 - middle ear

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".^[1] 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 in 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.^[2] 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.

(Could somebody re-write this so that the "lever arm factor of 1.3" and "17 fold larger" etc parts have a little more reality to it? Cheers, anon.)

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, mastoid process 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.

References

1. ^ Joseph D. Bronzino (2006). Biomedical Engineering Fundamentals. CRC Press. ISBN 0849321212.
2. ^ Koike et al.: Modeling of the human middle ear J. Acoust. Soc. Am., Vol. 111, No. 3, March 2002

8 - nasal turbinates or nasal concha

In anatomy, a turbinate (or nasal concha) is a long, narrow and curled bone shelf (shaped like an elongated sea-shell) which protrudes into the breathing passage of the nose. Turbinate bone refers to any of the scrolled spongy bones of the nasal passages in humans and other vertebrates. ^[1]

In humans, the turbinates divide the nasal airway into three groove-like air passages –and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface of cilia and climate controlling tissue.

Structure and functions of turbinates

Turbinates are composed of pseudostratified columnar, ciliated respiratory epithelium with a thick, vascular and erectile glandular tissue layer. ^[2] The turbinates are located laterally in the nasal cavities, curling medially and downwards into the nasal airway. Each pair is composed of one turbinate in either side of the nasal cavity, divided by the septum.^[2]

The inferior turbinates are the largest turbinates, and can be as long as the index finger, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.^[1]

The middle turbinates are smaller, usually as long as the pinky finger. They project downwards over the openings of the maxillary and ethmoid sinuses, and act as buffers to protect the sinuses from coming in direct contact with pressurized nasal airflow. Most inhaled airflow travels between the inferior turbinate and the middle turbinate.^[1]

The superior turbinates are smaller structures, connected to the middle turbinates by nerve-endings, and serve to protect the olfactory bulb.^[1]

Role of turbinates in the respiratory system

The turbinates compose most of the mucosal tissue of the nose and are required for functional respiration. The turbinates are enriched with airflow pressure and temperature sensing nerve receptors (linked to the “trigeminal” nerve route, the fifth cranial nerve), allowing for tremendous erectile capabilities of nasal congestion and decongestion (very much like the penis), in response to the climatic conditions and changing needs of the body.^[2]

The turbinates are also responsible for filtration, heating and humidification of air inhaled through the nose. Of these three, filtration is the most important reason to breathe through the nose. As air passes over the turbinate tissues it is heated to body temperature, humidified (up to 98% water saturation) and filtered.^[2]

Role of turbinates as an immunological defense

The respiratory epithelium which covers the erectile tissue (or Lamina propria) of the turbinates plays a major role in the body’s first line of immunological defense. The respiratory epithelium is partially composed of mucus producing goblet cells. This secreted mucus covers the nasal cavities, and serves as a filter, by trapping air-borne particles larger than 2 to 3 micrometers. The respiratory epithelium also serves as a means of access for the lymphatic system which protects the body from being infected by viruses or bacteria.^[1]

Role of turbinates in olfaction

The turbinates provide, first and foremost, the humidity needed to preserve the delicate olfactory (smell) epithelium needed to keep the olfactory receptors healthy and alert. If the epithelial layer gets dry or irritated, it may cease to function. This is usually a temporary condition, but over time, may lead to chronic anosmia^[2]. The turbinates also increase the surface area of the inside of the nose, and by directing and deflecting airflow across the maximum mucosal surface of the inner nose, they are able to propel the inspired air. This, coupled with the humidity and filtration provided by the turbinates, helps to carry more scent molecules towards the higher, and very narrow regions of the nasal airways, where olfaction nerve receptors are located^[1].

The superior turbinates literally hood-over, and protect the nerve axons piercing through the cribriform plate (a porous bone plate that separates the nose from the brain) into the nose. Some areas of the middle turbinates are also innervated by the olfactory bulb. All three turbinates are innervated by pain and temperature receptors, via the trigeminal nerve (or, the fifth cranial nerve)^[2]. Research has shown that there is a strong connection between these nerve endings and activation of the olfactory receptors, but science has yet to fully explain this interaction.

Turbinate dysfunction

Large, swollen turbinates may lead to blockage of nasal breathing. Allergies, exposure to environmental irritants, or a persistent inflammation within the sinuses, can lead to turbinate swelling. Deformity of the nasal septum can also result in enlarged turbinates. ^[3]

Treatment of the underlying allergy or irritant may reduce turbinate swelling. In cases that do not resolve, or for treatment of deviated septum, turbinate reduction surgery may be required. Generally, because the turbinates are essential for respiration, only small amounts of turbinate tissue are removed. Extensive reduction of the inferior or middle turbinates can cause empty nose syndrome.

References

1. ^ ^{a b c d e f} Anatomy of the Human Body Gray, Henry (1918) The Nasal Cavity.
2. ^ ^{a b c d e f} Turbinate Dysfunction: Focus on the role of the inferior turbinates in nasal airway obstruction. S.S. Reddy, et al. Grand Rounds Presentation, UTMB, Dept. of Otolaryngology
3. ^ ^{a b} Reduction/Removal of the Inferior Turbinate From the Sinus Info Center.

7 - perforated ear drum

Perforated Eardrum Overview

Your eardrum (tympanic membrane) is a thin, oval layer deep in your ear canal. It helps protect your delicate middle and inner ear from the outside world.

It is called an eardrum because it looks and acts like a drum. The eardrum receives vibrations from the outer ear and transmits them to the small hearing bones, or ossicles, of the middle ear.

Because it is so thin, your eardrum can be ruptured or punctured. The hole exposes the middle and inner ear to damage or infection.

Perforated Eardrum Causes

• Infection of the middle or outer ear is the most common cause of a ruptured eardrum.
• Infections can be caused by viruses, bacteria, or fungi.
• Infections increase the pressure behind your eardrum, stretching the drum and causing pain.

• When your eardrum can no longer stretch, it bursts or tears.
• Frequently, your pain gets better, because the pressure is now relieved. Sometimes, however, your pain can actually get worse.

• Trauma can also cause perforation.
• Blunt or penetrating trauma, such as from a fall on the side of your head or a stick that goes deep in your ear
• Rapid changes in pressure, like with scuba diving or going up in an elevator too fast (see ear pain with scuba diving or ear squeeze)

• You can rupture your eardrum in other ways.
• Slaps to the ear, such as a fall while water skiing or a hand slap to the side of the head
• Lightning blasts
• Blast waves from gunshots, fireworks, and other loud noises
• Changes in air pressure during flying or diving
• Sharp objects or cotton-tipped swabs
• Motor vehicle accidents
• Falls
• Sports injuries

Perforated Eardrum Symptoms

• Pain is the most common symptom.

• You may notice only some general discomfort.
• You may notice immediate intense pain.
• You may just feel as if something is not right with your ear.

• Other common symptoms

• Vertigo (spinning sensation)
• Ringing
• Buzzing
• Roaring
• Clicking
• Hearing change or loss
• Fluid or blood draining from your ear

When to Seek Medical Care

Call your doctor immediately if you have a ruptured eardrum and any of the following occur:

• An uncontrolled spinning sensation

• Difficulty walking

• An abrupt change in your hearing

• A change in your ability to taste foods

• You accidentally put your ear under water

The following symptoms suggest a potentially life-threatening complication and require immediate medical evaluation:

• Stiff neck

• High fever

• The worst headache of your life

• Numbness or weakness in face, arms, or legs

• Difficulty talking or opening mouth

• Continued vomiting

• Pain in the bone behind your ear

• Abrupt change in vision

• Difficulty staying awake

Exams and Tests

The doctor can diagnose eardrum rupture by doing a history and looking in your ear with an otoscope—a special magnifier with a light.

• Occasionally, very small holes can be difficult to identify and may require further testing.

• Tympanogram - A test that uses a short burst of air against your eardrum

• Audiogram – A hearing test

Perforated Eardrum Treatment

Surgery

Some large holes or nonhealing small holes require surgery.

• Surgical procedures are performed with general anesthetics. Most people go home from the hospital or clinic on the same day.

• An ear, nose, and throat specialist (otolaryngologist) may graft or patch your eardrum with paper, fat, muscle, or other material.

• These materials act as a bridge, allowing the tympanic membrane to grow together.

Next Steps

Prevention

Some causes of ruptured eardrums cannot be prevented or avoided. A little care can lower your risk.

• Treat ear infections early.

• Avoid flying or scuba diving if you have an upper respiratory tract infection.

• If you must fly or dive, plug your nose and swallow to help equalize the pressure.

• Never put anything in your ear.

• Wear proper ear protection.

Outlook

After a few weeks, you should notice no long-term symptoms.

Rarely, someone gets a dangerous infection that spreads into the brain or skull. This requires immediate hospitalization or surgery. Also, if you have symptoms of severe dizziness and vomiting, facial paralysis, or hearing loss, more extensive surgery of your inner or middle ear may be required instead of just patching the eardrum.

Synonyms and Keywords

ruptured eardrum, ruptured tympanic membrane, hole in eardrum, torn eardrum, bad ear, inner ear, perforated eardrum

6 - snoring

Snoring Overview

Snoring is the noise produced during sleep by vibrations of the soft tissues at the back of your nose and throat. The noise is created by turbulent flow of air through narrowed air passages. In general and in most cases, snoring has no medical significance unless it keeps you or others from sleeping. However, a more serious problem related to snoring can occur when those same soft tissues block the air passages at the back of the throat while you are sleeping. This interferes with the ability to breathe. This condition is obstructive sleep apnea (OSA), and it can directly affect your health.

Snoring Causes

• The prevalence of obstructive sleep apnea increases with age.
• In people aged 30–60 years, 2% of all women and 4% of all men have OSA. Up to 60% of the elderly have the condition.
• Most people diagnosed with obstructive sleep apnea are obese. Increased neck fat is thought to narrow the airway, making breathing more difficult.
• Men are 7-10 times more likely to have obstructive sleep apnea than women.

More Snoring Symptoms

Obstructive sleep apnea is an extreme form of snoring in which your upper airway closes while you are asleep, causing an obstruction that prevents you from breathing for a brief period.

• The soft tissues of the throat, your soft palate, and the tongue collapse onto the back wall of the upper airway, forming a blockage that prevents air from entering your lungs.

• The negative pressure of inhaling pulls harder on your soft tissues, sealing the airway even more tightly.

• To breathe and get air to your lungs, you must awaken or arouse slightly and create tension in your muscles—including the tongue and throat—and open the airway.

• This process causes a distinctive snorting, startling, and awaking pattern.

o If you have sleep apnea, you begin snoring, then stop breathing for at least 10 seconds (apnea). The apnea temporarily quiets the snoring, after which you awaken with a large snort. This pattern occurs in 95% of people with sleep apnea.

o Each cycle of blockage (apnea) and awakening can last from 20 seconds to 3 minutes, repeating many times throughout the night. Five episodes per hour per night are common. More than 15 episodes per hour per night are the criteria used to diagnosis the condition referred to as sleep apnea.

o Some snorers can have anywhere from 100-600 episodes or cycles of sleeping and waking per night.

o Although people with sleep apnea may be completely unaware of this repeating sleep-snore-apnea-wake pattern, it is very disruptive to normal sleep patterns. Usually, it is the bed partner who is most aware of the condition. Relationships, along with school and job performance, often suffer because of persistent daytime fatigue that develops as a result of continuously disrupted sleep.

• Characteristics of obstructive sleep apnea
• Movement in the bed when you wake and change position to breathe more easily
• Excessive daytime sleepiness with napping that often does not fully rest you
• Mood changes such as anxiety and irritability
• Decreased sexual drive and depression

• The repeated cycles of snoring, apnea, and waking that characterize OSA can lead to adverse physical changes and complications such as these:
• High blood pressure
• Coronary artery disease, heart attacks, strokes
• Pulmonary hypertension
• Confusion
• Loss of memory
• Psychiatric disorders and impotence

• Americans have OSA than do whites.
• Most people with obstructive sleep apnea are older than 40 years. Weight gain and a decrease in muscle tone occur with aging, and these may play a role in increasing the incidence of OSA.
• Sleep apnea is more common in postmenopausal women.
• Family history and genetics play a role.
• Polio and muscular dystrophy increase the chance of obstructive sleep apnea, as do other medical conditions such as sinus infections, allergies, colds and nasal tumors, and hypothyroidism (underactive thyroid gland).

When to Seek Medical Care

If you or someone close to you is not sleeping well because of snoring or sleep apnea, visiting your doctor may be helpful. This should be by appointment, because these are not emergency cases and sometimes extra time is scheduled for the evaluation.

A doctor's visit may be particularly important if you are doing any of the following:

• Falling asleep during normal waking hours

• Becoming irritable

• Losing concentration

• Becoming depressed

Exams and Tests

A doctor will complete a general physical examination, paying particular attention to your nose and throat.

• Your weight and blood pressure will be evaluated. Your blood may be tested for thyroid function.

• An otolaryngologist (ear, nose, and throat doctor) can look into your airway with a fiberoptic device to see if the nasal passages are open or partially blocked (septal deviation) or if there are any masses (tumors) present in your nose, throat, or upper airway that may be causing the snoring.

• For severe cases, you may be referred for a sleep laboratory test. This overnight test monitors up to 16 different bodily functions while you sleep. The results of these tests can help define the level and severity of sleep apnea if it is present.

Snoring Treatment

Self-Care at Home

Many remedies are available over-the-counter in drug stores, but most do not help correct snoring or sleep apnea.

• Because you tend to snore more when sleeping on your back, one useful technique is to try to keep from sleeping in that position. One way is to wear a pocket T-shirt backward with a tennis ball in the pocket. You will be less likely to sleep on your back because it is very uncomfortable to sleep on a tennis ball.

• Try losing some weight. As little as 10 pounds might make the difference.

• Avoid alcohol, especially in the 4 hours before going to sleep.

• Avoid using sedatives and narcotic medications. Alcohol, sedatives, and narcotics cause relaxation of your throat muscles and increase the tendency for airway obstruction related to snoring.

Medical Treatment

For mild forms of snoring caused by swelling of the lining of your nose, a doctor may prescribe an inhaled steroid preparation.

For more severe forms of sleep apnea, surgical procedures (see Surgery) or continuous positive airway pressure may be tried:

• Continuous positive airway pressure (CPAP)
• CPAP is a device that includes a mask that fits snugly over your nose and mouth and is held in place with head straps. The mask is connected to a blower that generates pressurized air. You wear it while sleeping.
• The controlled pressure works as an air splint to keep the soft tissue of the nose and throat in place and the airway open.
• This noninvasive therapy works for 95% of people with sleep apnea.

Surgery

• Somnoplasty: This is an outpatient surgical procedure performed with the patient under local anesthetic. It takes about a half-hour. During the procedure, a small electrode is placed in your anesthetized soft palate and heated up. The heat that is generated by the electrode causes the extra soft tissue at the back of the throat to shrink and contract over a few weeks.
• Tonsillectomy and adenoidectomy involves removing the tonsils and adenoids from the back of the throat.
• Your doctor may recommend cutting out certain tissues of the soft palate to remove the obstructing tissue.

Next Steps

Outlook

With proper treatment, most people with snoring-related problems improve. People who have obstructive sleep apnea will most likely benefit greatly with treatment. Any improvement in the condition will most likely result in more restful sleep and a reduction in daytime fatigue.

• Sleeping partners appreciate almost any reduction in snoring-related noise.

• It is generally well worth the effort to have this condition evaluated.

Synonyms and Keywords

snoring, obstructive sleep apnea, OSA, fatigue, irritability

5 - cartilages of the nose ( external nose )

the External Nose (Nasus Externus; Outer Nose)—The external nose is pyramidal in form, and its upper angle or root is connected directly with the forehead; its free angle is termed the apex. Its base is perforated by two elliptical orifices, the nares, separated from each other by an antero-posterior septum, the columna. The margins of the nares are provided with a number of stiff hairs, or vibrissæ, which arrest the passage of foreign substances carried with the current of air intended for respiration. The lateral surfaces of the nose form, by their union in the middle line, the dorsum nasi, the direction of which varies considerably in different individuals; the upper part of the dorsum is supported by the nasal bones, and is named the bridge. The lateral surface ends below in a rounded eminence, the ala nasi. Structure.—The frame-work of the external nose is composed of bones and cartilages; it is covered by the integument, and lined by mucous membrane. The bony frame-work occupies the upper part of the organ; it consists of the nasal bones, and the frontal processes of the maxillæ. The cartilaginous frame-work (cartilagines nasi) consists of five large pieces, viz., the cartilage of the septum, the two lateral and the two greater alar cartilages, and several smaller pieces, the lesser alar cartilages . The various cartilages are connected to each other and to the bones by a tough fibrous membrane. The cartilage of the septum (cartilago septi nasi) is somewhat quadrilateral in form, thicker at its margins than at its center, and completes the separation between the nasal cavities in front. Its anterior margin, thickest above, is connected with the nasal bones, and is continuous with the anterior margins of the lateral cartilages; below, it is connected to the medial crura of the greater alar cartilages by fibrous tissue. Its posterior margin is connected with the perpendicular plate of the ethmoid; its inferior margin with the vomer and the palatine processes of the maxillæ.

It may be prolonged backward (especially in children) as a narrow process, the sphenoidal process, for some distance between the vomer and perpendicular plate of the ethmoid. The septal cartilage does not reach as far as the lowest part of the nasal septum. This is formed by the medial crura of the greater alar cartilages and by the skin; it is freely movable, and hence is termed the septum mobile nasi. The lateral cartilage (cartilago nasi lateralis; upper lateral cartilage) is situated below the inferior margin of the nasal bone, and is flattened, and triangular in shape. Its anterior margin is thicker than the posterior, and is continuous above with the cartilage of the septum, but separated from it below by a narrow fissure; its superior margin is attached to the nasal bone and the frontal process of the maxilla; its inferior margin is connected by fibrous tissue with the greater alar cartilage. The greater alar cartilage (cartilago alaris major; lower lateral cartilage) is a thin, flexible plate, situated immediately below the preceding, and bent upon itself in such a manner as to form the medial and lateral walls of the naris of its own side. The portion which forms the medial wall (crus mediale) is loosely connected with the corresponding portion of the opposite cartilage, the two forming, together with the thickened integument and subjacent tissue, the septum mobile nasi. The part which forms the lateral wall (crus laterale) is curved to correspond with the ala of the nose; it is oval and flattened, narrow behind, where it is connected with the frontal process of the maxilla by a tough fibrous membrane, in which are found three or four small cartilaginous plates, the lesser alar cartilages (cartilagines alares minores; sesamoid cartilages). Above, it is connected by fibrous tissue to the lateral cartilage and front part of the cartilage of the septum; below, it falls short of the margin of the naris, the ala being completed by fatty and fibrous tissue covered by skin. In front, the greater alar cartilages are separated by a notch which corresponds with the apex of the nose.

The muscles acting on the external nose have been described in the section on Myology. The integument of the dorsum and sides of the nose is thin, and loosely connected with the subjacent parts; but over the tip and alæ it is thicker and more firmly adherent, and is furnished with a large number of sebaceous follicles, the orifices of which are usually very distinct. The arteries of the external nose are the alar and septal branches of the external maxillary, which supply the alæ and septum; the dorsum and sides being supplied from the dorsal nasal branch of the ophthalmic and the infraorbital branch of the internal maxillary. The veins end in the anterior facial and ophthalmic veins. The nerves for the muscles of the nose are derived from the facial, while the skin receives branches from the infratrochlear and nasociliary branches of the ophthalmic, and from the infraorbital of the maxillary.

4 - external ear ( outer ear )

The outer ear is the external portion of the ear, which consists of the pinna, concha, and auditory meatus. It gathers sound energy and focuses it on the eardrum (tympanic membrane). One consequence of the configuration of the external ear is to selectively boost the sound pressure 30- to 100-fold for frequencies around 3000 Hz. This amplification makes humans most sensitive to frequencies in this range - and also explains why they are particularly prone to acoustical injury and hearing loss near this frequency. Most human speech sounds are also distributed in the bandwidth around 3 kHz.

Pinna, or auricle

The visible part is called the pinna and functions to collect and focus sound waves. It is composed of a thin plate of yellow fibrocartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the external acoustic meatus by fibrous tissue. Many mammals can move the pinna (with the auriculares muscles) in order to focus their hearing in a certain direction in much the same way that they can turn their eyes. Most humans, unlike most other mammals, do not have this ability.

Ear canal, or external auditory meatus

From the pinna the sound pressure waves move into the ear canal, a simple tube running to the middle ear. This tube leads inward from the bottom of the auricula and conducts the vibrations to the tympanic cavity and amplifies frequencies in the range 3 kHz to 12 kHz.