Nasal turbinates or nasal conchae are the narrow, long, and curled bony shelves, which tend to protrude inside the nasal cavity . These bony projections run medial and downwards in the nasal cavity. All types of conchae help in dividing the nasal cavity into air passages (groove-like) that are essential for nasal breathing. In addition, these bones help provide significant landmarks to the surgical procedures and base of the skull (1).
Nasal conchae divide into three types:
- Superior nasal concha – it is a projection from the ethmoidal labyrinth’s medial surface. In terms of size, it is the smallest concha in the body. This concha sits right above the middle concha’s posterior part. Superior concha serves the role of protecting the olfactory bulb.
- Middle nasal concha – a projection of bone from the ethmoidal labyrinth’s medial surface. It is usually the size of a fifth finger that opens directly into the ethmoid and maxillary sinuses. This concha acts as a buffer for the protection of sinuses from the increased pressure in nasal airflow.
- Inferior nasal concha – it is an independent bone that doesn’t project from any other structure. Of all the conchae, the inferior concha is the largest one which may equal the size of the index finger. Inferior conchae are responsible for giving airflow direction, filtration, heating, and humidification of the air entering the nasal cavity.
Meatuses are the passages that lie underneath the area of the inferior conchae. Each of these meatuses is capable of communicating with the nasal cavity independently (2).
Meatuses divide into:
IIt lies under the surface of the inferior concha, and of all the three meatuses, the inferior concha is the largest.
The Nasolacrimal duct opens into the posterior 2/3 rd and anterior 1/3 rd junction of the inferior nasal meatus, and the Hasner’s valve or lacrimal folds help in guarding the opening of the nasal meatus.
It lies just below the middle concha.
Middle meatus shows the following features:
- Ethmoidal bulla – a rounded elevation of middle ethmoidal sinuses
- Hiatus semilunaris – a deep semicircular sulcus lying below the bulla
- Infundibulum – a short passage present at the anterior ending of the hiatus
- Frontal air sinus opening – present in the hiatus semilunaris’ anterior part
- Anterior ethmoidal air sinus opening – lies behind the frontal air sinus’ opening
- Maxillary air sinus opening – lies in hiatus semilunaris’ posterior part. It often represents two openings.
It lies just below the superior concha. Of all the meatuses, superior meatus is the shallowest and shortest meatus in size. This is because the superior meatus receives openings from the posterior ethmoidal sinuses.
In the lateral wall, four quadrants of the nasal conchae are supplied by general sensory nerve branches of the trigeminal nerve (3,4).
All the four quadrants have their innervations from:
- Anterosuperior quadrant – innervation from ophthalmic nerve’s anterior ethmoidal branch
- Anteroinferior quadrant – innervation from the infraorbital branch and maxillary nerve continuation as anterior superior alveolar nerve
- Posterosuperior quadrant – innervation from the lateral posterior superior nasal nerve from the ganglion (pterygopalatine ganglion)
- Posterioinferior quadrant – innervation from pterygopalatine ganglion’s anterior palatine branch
Olfactory or special sensory nerves have distributions to the lateral wall’s upper part just under the ethmoid’s cribriform plate to the superior concha. Olfactory mucosa lies in two parts as partially over the nasal septum and on the lateral wall.
Muscles of nasal group
Muscles that correlate with the nasal group are depressor septi, procerus, and nasalis. Levator labii superioris alaeque nasi is a muscle associated with the oral group but functions with the nose.
Procerus has its origin from the nasal bone and inserts in the glabella (overlying skin). Wrinkling of skin over the nose bridge by the downward pull of the medial angle of the eyebrows is the function of procerus.
Venous drainage of the nasal conchae is from the veins forming a plexus and draining into:
- Facial vein (anteriorly)
- Pharyngeal plexus
- Pterygoid veins plexus
The nasal cavity and other structures have a rich supply of blood. Both the external and internal carotid arteries give blood supply to the nose (3,4).
Branches of the internal carotid artery:
- Posterior and anterior ethmoidal arteries
Ethmoidal arteries are the ophthalmic artery branches that descend into the cavity of the nose via a cribriform plate.
External carotid branches:
Branches of the external carotid artery are:
- Lateral nasal artery
- Greater palatine artery
- Sphenopalatine artery
- Superior labial artery
The facial artery gives blood supply to the anteroinferior quadrant of the conchae. A few branches of the sphenopalatine artery supply the posterosuperior quadrant.
Lymphatic drainage for nasal conchae
For lymphatic drainage, lymphatics from the lateral wall’s anterior half pass to submandibular nodes. Furthermore, lymphatics from the posterior half pass to the upper deep cervical and retropharyngeal nodes (5).
Functions of the nasal conchae
The nose is the respiratory and olfactory organ of the body. The nasal cavity consists of several compartments and structures as conchae, meatuses, cribriform plates, and a lot more.
There are a few basic functions of the nasal cavity:
- Humidification and heating of the inspired air
- Removal of pathogens and other dirt materials from the inspired air
- Responsible for letting the olfactory nerves work for smelling and distinguishing different smells
- Clearance and drainage of lacrimal ducts and paranasal sinuses
Acute invasive fungal sinusitis is the infection of sinuses in conditions like HIV, transplantation, and diabetic ketoacidosis. The responsible pathogens for this infection are Absidia, Rhizopus, Aspergillus, and Mucor.
JNA (Juvenile Nasopharyngeal Angiofibroma)
JNA is the common mass (vascular) found in the nasal cavity of adolescent males. The common causes of the JNA are nasal obstruction and recurrent epistaxis. The common sites for the production of these masses are the nasal cavity roof accompanying sphenopalatine foramen (7).
Inferior turbinate hypertrophy is the most common characteristic of the allergic rhinitis condition.
Following are the most common features of allergic rhinitis:
- Nasal blockage
- Frequent sneezing
- Excessive water-like discharge from the nasal cavity or nose
Trauma or fracture of the nasal bone can lead to profuse bleeding in the nasal cavity. Fractures of the nasal bone are frequent problems in cases of physical traumas.
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- Tatlisumak E, Aslan A, Cömert A, Ozlugedik S, Acar HI, Tekdemir I. Surgical anatomy of the nasolacrimal duct on the lateral nasal wall as revealed by serial dissections. Anatomical science international. 2010 Mar 1;85(1):8-12.
- Al-Shouk AA, Tatar İ. The blood supply of the inferior nasal concha (turbinate): A cadaveric anatomical study. Anatomical Science International. 2021 Jan;96:13-9.
- Perez-Pinas I, Sabate J, Carmona A, Catalina-Herrera CJ, Jimenez-Castellanos J. Anatomical variations in the human paranasal sinus region studied by CT. The Journal of Anatomy. 2000 Aug;197(2):221-7.
- Ozcan KM, Selcuk A, Özcan I, Akdogan O, Dere H. Anatomical variations of nasal turbinates. Journal of Craniofacial Surgery. 2008 Nov 1;19(6):1678-82.
- Ray B, Singh LK, Das CJ, Roy TS. Ectopic supernumerary tooth on the inferior nasal concha. Clinical Anatomy. 2006 Jan;19(1):68-74.
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