Understanding Your Nasal Turbinates

Anatomy, Function, and Disorders of the Nasal Conchae

Nasal cavity
What is the structure and function of the nasal turbinates?. Encyclopaedia Britannica/UIG/Getty Images

If you have heard a reference to your "nasal turbinates" where are these located? What is the anatomy of this part of the nose, what is its function, and what disorders may occur?

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:

  1. The nasolacrimal duct (tear duct) empties any drainage from the eyes, starting at external eye and emptying into the inferior meatus.
  1. The head of the nasal wall, inferior meatus, and osseous piriform aperture makes 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 meatus and the middle meatus.

This space is important for:

  1. Drainage of three of the paranasal sinuses; the maxillary, frontal, and front (anterior) ethmoid sinuses.
  2. 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 meatus and the superior meatus. 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:

  1. Drainage of two of the paranasal sinuses: the sphenoid and back (posterior) ethmoid sinuses.
  2. Like the middle meatus, airflow through this passageway (which interacts with sinus cavities) helps to modify our vocal features.
  3. Mucus 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).

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 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:

  1. Congested passageways (narrow) allows the glands to "recharge."
  2. Congested passageways also are thought to allow for mucus to be removed.
  3. 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
  • Sleep apnea: Abnormalities in the nasal turbinates is one of the causes of sleep apnea.
  • 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 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.)
  • Auditory tube dysfunction: Enlargements or other problems with the turbinates is one of the causes of auditory tube dysfunction (also called eustachian 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, a turbinate reduction can be performed during endoscopic sinus surgery. This procedure requires general anesthesia and is typically performed in a same day surgery clinic.

Bottom Line on the Anatomy and Physiology of the Nasal Turbinates and Their Role in Disease

The nasal turbinates are comprised of three or four structures which 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.

Sources:

Terzi, S., Dursun, E., Celiker, F. et al. The Effects of Choanal Atresia on Development of the Paranasal Sinuses and Turbinates. Surgical and Radiologic Anatomy. 2017 Mar 13. (Epub ahead of print).

Turner, J., Lal, D. and J. Nayak. American Rhinologic Society. Nasal Anatomy. Updated 01/20/15. http://care.american-rhinologic.org/nasal_anatomy

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