Nasal Turbinates: Definition
Turbinates, which are also called nasal concha or conchae (plural), are shell-shaped networks of bones, vessels, and tissue within the nasal passageways. These structures are responsible for warming, humidifying, and filtering the air we breathe. Normally there are three turbinates including the superior (upper), middle, and inferior (lower) turbinates. However, occasionally you can have a fourth turbinate (called the supreme turbinate) which is situated higher than the superior turbinate.
In between each turbinate is space (known as meati), each with a name that coincides with the name of the turbinate that is directly above the space. These spaces form our nasal passageways which direct air flow through our nose.
Structure (Anatomy) of the Nasal Turbinates (Conchae)
As noted, the nasal turbinates are broken down into three sections, the upper, middle, and lower conchae.
Inferior Meatus (Lower Conchae)
The inferior meatus is the space between the floor of the nasal cavity and the inferior turbinate. This is the largest of the air spaces. This passageway serves multiple purposes:
The nasolacrimal duct (tear duct) empties any drainage from the eyes, starting at the external eye and emptying into the inferior meatus. The head of the nasal wall, inferior meatus, and osseous piriform aperture make up the nasal valve. The nasal valve is the narrowest area in the nasal cavity and is often the site of obstruction (collapse) due to a deviated septum or other nasal abnormalities.
Middle Meatus
The middle meatus is the nasal passageway that lies between the inferior turbinate and the middle turbinate.
This space is important for:
Drainage of three of the paranasal sinuses; the maxillary, frontal, and front (anterior) ethmoid sinuses. Airflow through the paranasal sinuses which creates the tones of our voices.
Superior Meatus (Upper Conchae)
The Superior meatus is the nasal space that lies between the middle turbinate and the superior turbinate. This is normally the top-most nasal passageway, however, occasionally there is also a supreme turbinate that is above the superior turbinate. Functions of this passageway include:
Drainage of two of the paranasal sinuses: the sphenoid and back (posterior) ethmoid sinuses. Like the middle meatus, airflow through this passageway (which interacts with sinus cavities) helps to modify our vocal features. Mucous membranes of the superior turbinate (along with the upper part of the nasal septum, which divides the left and right nostrils) are lined with nerve endings which are used to interpret smell. This is why disorders in this turbinate may result in disturbances in the sense of smell (olfaction). There are even more smell or olfactory cells even higher up at the roof of the nasal cavity.
The upper and middle conchae are part of the ethmoid bone, but the lower conchae is an independent structure.
Function (Physiology) of the Turbinates: Regulation of the Nasal Cycle
Every one to seven hours, your nasal passageways undergo a cycle of constricting (shrinking) one turbinate while the other turbinate, on the opposite side of the nose, swells. This subsequently makes some of the passageways narrow, restricting airflow, while enlarging the other airway and improving airflow. During nasal cycle changes, you will not feel congested since your overall airway resistance has not changed.
The purpose of the nasal cycle is not fully understood but common theories include:
Congested passageways (narrow) allows the glands to “recharge. “Congested passageways also are thought to allow for mucus to be removed. Constricted passageways (enlarged) allows for improved humidification and easier airflow.
Turbinate Disorders
The nasal turbinates can be associated with several disorders. Oftentimes, the symptom associated with these disorders is congestion. Turbinate disorders include:
The common cold: We have all experienced problems with our nasal turbinates when we suffer the congestion of the common cold. Allergies Concha Bullosa: Concha bullosa is a fairly common medical condition in which there is an air pocket (pneumatization) in the middle meatus. This air pocket can lead to inadequate drainage of the sinuses and subsequent sinus infections. Nasal valve collapse: The nasal valve is the narrowest part of the nasal airway with the lower conchae making up a part of this structure. This airway may become narrowed even further (nasal valve collapse) due to trauma, a deviated nasal septum, or due to rhinoplasty (plastic surgery on the nose). Eustachian tube dysfunction: Enlargements or other problems with the turbinates is one of the causes of eustachian tube dysfunction (also called auditory tube dysfunction). Choanal Atresia: Choanal atresia is a blockage of the nasal passages by tissue often present from birth, and can affect the development of the lower and middle turbinates.
Correcting Turbinate Disorders
Many turbinate disorders resolve on their own, but occasionally treatment is needed to correct the problem. When turbinate disorders need to be corrected, medications can often help; occasionally, a turbinate reduction can be performed alone or during endoscopic sinus surgery. This procedure requires general anesthesia and is typically performed in a same day surgery clinic.
A Word From Verywell
The nasal turbinates are comprised of three or four structures that serve the function of warming, humidifying, and filtering the air that we breathe. Abnormalities in the turbinates often result in congestion, as occurs with the common cold and allergies. Structural changes in the turbinates such as concha bullosa and choanal atresia can also result in symptoms. When severe, surgery (turbinate reduction) may be necessary to reduce symptoms and restore function to this part of our anatomy.
