Turbinate
Encyclopedia
In anatomy
, a nasal concha (or turbinate) is a long, narrow and curled bone shelf (shaped like an elongated sea-shell) that protrudes into the breathing passage of the nose
. Turbinate bone refers to any of the scrolled spongy bone
s of the nasal passages
in vertebrates.
In humans, the turbinates divide the nasal airway into four 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.
columnar
, ciliated respiratory epithelium
with a thick, vascular
, and erectile glandular tissue layer.
The turbinates are located laterally in the nasal cavities, curling medially and downward into the nasal airway. Each pair is composed of one turbinate in either side of the nasal cavity, divided by the septum
.
The inferior turbinates
are the largest turbinates, and can be as long as the index finger
in humans, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.
The middle turbinates
are smaller. In humans, they are usually as long as the little 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.
The superior turbinates
are smaller structures, connected to the middle turbinates by nerve-endings, and serve to protect the olfactory bulb
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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, in response to the climatic conditions and changing needs of the body. The flow of blood to the nasal mucosa, in particular the venous plexus of the conchae is regulated by the pterygopalatine ganglion
and heats or cools the air in the nose.
The nasopulmonary and nasothoracic reflex
es regulate the mechanism of breathing through deepening the inhale. Triggered by the flow of the air, the pressure of the air in the nose, and the quality of the air, impulses from the nasal mucosa are transmitted by the trigeminal nerve to the breathing centres
in the brainstem, and the generated response is transmitted to the bronchi
, the intercostal muscles, and the diaphragm
.
The turbinates are also responsible for filtration, heating, and humidification of air inhaled through the nose. Of these three, filtration is achieved mostly by other more effective means such as mucous and cilla. As air passes over the turbinate tissues, it is heated to 32°C to 34°C, humidified (up to 98% water saturation
) and filtered.
that 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.
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
. 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.
The superior turbinates completely cover 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). 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.
s, or a persistent inflammation
within the sinuses can lead to turbinate swelling. Deformity of the nasal septum
can also result in enlarged turbinates.
Treatment of the underlying allergy or irritant may reduce turbinate swelling. In cases that do not resolve, or for treatment of deviated septum
, turbinate surgery may be required.
There are different forms of turbinate surgery: Somnoplasty
- bipolar radiofrequency ablation - a technique used for coblation tonsillectomy, is also used for the treatment of swollen turbinates; reduction by the use of pure heat can be equally effective as can turbinate sectioning. In the case of sectioning, because the turbinates are essential for respiration, only small amounts of turbinate tissue should be removed. Extensive reduction of the inferior or middle turbinates can cause empty nose syndrome
.
Concha bullosa
is an abnormal pneumatization of the middle turbinate, which may interfere with normal ventilation of sinus ostia and can result in recurrent sinusitis.
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
, a nasal concha (or turbinate) is a long, narrow and curled bone shelf (shaped like an elongated sea-shell) that protrudes into the breathing passage of the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
. Turbinate bone refers to any of the scrolled spongy bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s of the nasal passages
Nasal cavity
The nasal cavity is a large air filled space above and behind the nose in the middle of the face.- Function :The nasal cavity conditions the air to be received by the other areas of the respiratory tract...
in vertebrates.
In humans, the turbinates divide the nasal airway into four 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 pseudostratifiedPseudostratified epithelium
A pseudostratified epithelium is a type of epithelium that, though comprising only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified epithelia...
columnar
Columnar epithelia
Columnar epithelia are epithelial cells whose heights are at least four times their width. Columnar epithelia are divided into simple , and stratified .* Simple columnar epithelia* Stratified columnar epithelia...
, ciliated respiratory epithelium
Respiratory epithelium
Respiratory epithelium is a type of epithelium found lining the respiratory tract, where it serves to moisten and protect the airways. It also functions as a barrier to potential pathogens and foreign particles, preventing infection and tissue injury by action of the mucociliary escalator.-...
with a thick, vascular
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
, and erectile glandular tissue layer.
The turbinates are located laterally in the nasal cavities, curling medially and downward into the nasal airway. Each pair is composed of one turbinate in either side of the nasal cavity, divided by the septum
Nasal septum
The nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....
.
The inferior turbinates
Inferior nasal conchae
The inferior nasal concha is one of the turbinates in the nose. It extends horizontally along the lateral wall of the nasal cavity [Fig. 1] and consists of a lamina of spongy bone, curled upon itself like a scroll...
are the largest turbinates, and can be as long as the index finger
Index finger
The index finger, , is the first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger...
in humans, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.
The middle turbinates
Middle nasal concha
The medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha....
are smaller. In humans, they are usually as long as the little finger
Little finger
The little finger, often called the pinky in American English, pinkie in Scottish English , or small finger in medicine, is the most ulnar and usually smallest finger of the human hand, opposite the thumb, next to the ring finger.-Muscles:There are four muscles that...
. They project downwards over the openings of the maxillary
Maxillary sinus
The pyramid shaped maxillary sinus is the largest of the paranasal sinuses, and drains into the nose. It is present at birth as rudimentary air cells, and develops throughout childhood.-General characteristics:...
and ethmoid
Ethmoid sinus
The ethmoid sinus is each of the two paranasal sinuses within the ethmoid bone, comprising the ethmoidal air cells and filled with air. These are divided into anterior, middle and posterior group. The ethmoidal air cells consist of numerous thin-walled cavities situated in the ethmoidal labyrinth...
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.
The superior turbinates
Superior nasal concha
The back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha....
are smaller structures, connected to the middle turbinates by nerve-endings, and serve to protect the olfactory bulb
Olfactory bulb
The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors.-Anatomy:In most vertebrates, the olfactory bulb is the most rostral part of the brain. In humans, however, the olfactory bulb is on the inferior side of the brain...
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Role of turbinates in the respiratory system
The turbinates compose most of the mucosal tissue of the noseHuman nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
and are required for functional respiration
Respiratory system
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...
. 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
Nasal congestion
Nasal congestion is the blockage of the nasal passages usually due to membranes lining the nose becoming swollen from inflamed blood vessels. It is also known as nasal blockage, nasal obstruction, blocked nose, stuffy nose, or stuffed up nose.Nasal congestion has many causes and can range from a...
and decongestion, in response to the climatic conditions and changing needs of the body. The flow of blood to the nasal mucosa, in particular the venous plexus of the conchae is regulated by the pterygopalatine ganglion
Pterygopalatine ganglion
The pterygopalatine ganglion is a parasympathetic ganglion found in the pterygopalatine fossa. It is one of four parasympathetic ganglia of the head and neck....
and heats or cools the air in the nose.
The nasopulmonary and nasothoracic reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
es regulate the mechanism of breathing through deepening the inhale. Triggered by the flow of the air, the pressure of the air in the nose, and the quality of the air, impulses from the nasal mucosa are transmitted by the trigeminal nerve to the breathing centres
Control of respiration
Control of ventilation refers to the physiological mechanisms involved in the control of physiologic ventilation. Gas exchange primarily controls the rate of respiration.The most important function of breathing is gas exchange...
in the brainstem, and the generated response is transmitted to the bronchi
Bronchus
A bronchus is a passage of airway in the respiratory tract that conducts air into the lungs. The bronchus branches into smaller tubes, which in turn become bronchioles....
, the intercostal muscles, and the diaphragm
Diaphragm
-Optics and photography:* Diaphragm , a stop in the light path of a lens, having an aperture that regulates the amount of light that passes* Diaphragm shutter, a type of leaf shutter consisting of a number of thin blades in a camera-Acoustics:...
.
The turbinates are also responsible for filtration, heating, and humidification of air inhaled through the nose. Of these three, filtration is achieved mostly by other more effective means such as mucous and cilla. As air passes over the turbinate tissues, it is heated to 32°C to 34°C, humidified (up to 98% water saturation
Dew point
The dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
) and filtered.
Role of turbinates as an immunological defense
The respiratory epitheliumRespiratory epithelium
Respiratory epithelium is a type of epithelium found lining the respiratory tract, where it serves to moisten and protect the airways. It also functions as a barrier to potential pathogens and foreign particles, preventing infection and tissue injury by action of the mucociliary escalator.-...
that covers the erectile tissue (or lamina propria
Lamina propria
The lamina propria is a constituent of the moist linings known as mucous membranes or mucosa, which line various tubes in the body ....
) of the turbinates plays a major role in the body’s first line of immunological defense. The respiratory epithelium is partially composed of mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
-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
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...
, which protects the body from being infected by viruses or bacteria.
Role of turbinates in olfaction
The turbinates provide, first and foremost, the humidity needed to preserve the delicate olfactory epitheliumEpithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
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
Anosmia
Anosmia is a lack of functioning olfaction, or in other words, an inability to perceive odors. Anosmia may be either temporary or permanent. A related term, hyposmia, refers to a decreased ability to smell, while hyperosmia refers to an increased ability to smell. Some people may be anosmic for one...
. The turbinates also increase the surface area
Surface area
Surface area is the measure of how much exposed area a solid object has, expressed in square units. Mathematical description of the surface area is considerably more involved than the definition of arc length of a curve. For polyhedra the surface area is the sum of the areas of its faces...
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.
The superior turbinates completely cover and protect the nerve axons piercing through the cribriform plate
Cribriform plate
The cribriform plate of the ethmoid bone is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities....
(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
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
and temperature receptors, via the trigeminal nerve
Trigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
(or, the fifth cranial nerve). 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 irritantIrritation
Irritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...
s, or a persistent inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
within the sinuses can lead to turbinate swelling. Deformity of the nasal septum
Nasal septum
The nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....
can also result in enlarged turbinates.
Treatment of the underlying allergy or irritant may reduce turbinate swelling. In cases that do not resolve, or for treatment of deviated septum
Deviated septum
Nasal septum deviation is a common physical disorder of the nose, involving a displacement of the nasal septum.-Causes:It is most frequently caused by impact trauma, such as by a blow to the face. It can also be a congenital disorder, caused by compression of the nose during childbirth...
, turbinate surgery may be required.
There are different forms of turbinate surgery: Somnoplasty
Somnoplasty
Somnoplasty is composed of the Latin root somnus meaning sleep, and the Greek word plastia meaning molding or formation. Somnoplasty is a medical treatment approved by the Food and Drug Administration to treat three conditions: habitual snoring, chronic nasal obstruction, and obstructive sleep...
- bipolar radiofrequency ablation - a technique used for coblation tonsillectomy, is also used for the treatment of swollen turbinates; reduction by the use of pure heat can be equally effective as can turbinate sectioning. In the case of sectioning, because the turbinates are essential for respiration, only small amounts of turbinate tissue should be removed. Extensive reduction of the inferior or middle turbinates can cause empty nose syndrome
Empty nose syndrome
Empty nose syndrome is a term that is used in otolaryngology to describe a nose that has been physiologically crippled by excessive surgical removal of turbinates in the nose in a surgical procedure known as 'turbinectomy' or 'conchotomy'...
.
Concha bullosa
Concha bullosa
A concha bullosa is a pneumatized cavity within a turbinate in the nose. Bullosa refers to the air-filled cavity within the turbinate. It is a normal anatomic variant seen in up to half the population...
is an abnormal pneumatization of the middle turbinate, which may interfere with normal ventilation of sinus ostia and can result in recurrent sinusitis.
See also
- Bone terminology
- Anatomical terms of locationAnatomical terms of locationStandard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...
- Superior nasal conchaSuperior nasal conchaThe back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha....
, middle nasal conchaMiddle nasal conchaThe medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha....
and inferior nasal concha - Empty nose syndromeEmpty nose syndromeEmpty nose syndrome is a term that is used in otolaryngology to describe a nose that has been physiologically crippled by excessive surgical removal of turbinates in the nose in a surgical procedure known as 'turbinectomy' or 'conchotomy'...
- Concha bullosaConcha bullosaA concha bullosa is a pneumatized cavity within a turbinate in the nose. Bullosa refers to the air-filled cavity within the turbinate. It is a normal anatomic variant seen in up to half the population...