Middle Nasal Concha

The middle nasal concha, also called the middle turbinate, is a curved bony projection extending medially from the lateral wall of the nasal cavity. It is part of the ethmoid bone and is covered by respiratory mucosa.

The middle nasal concha is an important anatomical landmark because it overlies the middle nasal meatus, a passage that receives drainage from several paranasal sinuses. Its position also contributes to the regulation of nasal airflow and increases the mucosal surface area available for conditioning inspired air.

Location

The middle nasal concha projects from the lateral wall of each nasal cavity.

It lies inferior to the superior nasal concha and superior to the inferior nasal concha, with the middle nasal meatus situated immediately beneath it.

Bony Origin

The middle nasal concha is a component of the ethmoid bone.

This distinguishes it from the inferior nasal concha, which is an independent facial bone rather than a projection of the ethmoid.

Relationship to the Ethmoid Bone

The ethmoid bone contributes extensively to the superior and lateral walls of the nasal cavity.

Both the superior and middle nasal conchae project from the ethmoidal labyrinth, while the intervening spaces form corresponding nasal meatuses.

Nasal Conchae

The principal nasal conchae are:

Superior nasal concha
Middle nasal concha
Inferior nasal concha

A small supreme nasal concha may also be present superior to the superior concha in some individuals.

Comparison of the Nasal Conchae

Concha	Bony Origin	Associated Space
Superior nasal concha	Ethmoid bone	Superior nasal meatus
Middle nasal concha	Ethmoid bone	Middle nasal meatus
Inferior nasal concha	Independent bone	Inferior nasal meatus

Shape and Orientation

The middle nasal concha is a thin, curved plate of bone projecting medially and somewhat inferiorly from the lateral nasal wall.

Its free border projects into the nasal airway, while its attached portion is continuous with the ethmoidal labyrinth.

Mucosal Covering

The bony middle nasal concha is covered by mucosa continuous with the lining of the nasal cavity.

Most of this surface is lined by respiratory mucosa containing ciliated pseudostratified columnar epithelium, goblet cells, and an underlying vascular lamina propria.

Middle Nasal Meatus

The middle nasal meatus is the passage located inferior and lateral to the middle nasal concha.

It is anatomically important because drainage pathways from the frontal sinus, maxillary sinus, and anterior and middle ethmoidal air cells are associated with this region.

Structures of the Middle Meatus

Important landmarks associated with the middle nasal meatus include:

Ethmoidal bulla
Hiatus semilunaris
Ethmoidal infundibulum
Opening of the maxillary sinus
Drainage pathways from the frontal sinus
Openings associated with anterior and middle ethmoidal air cells

Ethmoidal Bulla

The ethmoidal bulla is a rounded elevation on the lateral wall of the middle nasal meatus.

It is produced by underlying middle ethmoidal air cells. These cells commonly open on or near the surface of the bulla.

Hiatus Semilunaris

The hiatus semilunaris is a curved groove in the lateral wall of the middle meatus.

It lies inferior to the ethmoidal bulla and is closely related to the drainage pathway of the maxillary sinus and ethmoidal infundibulum.

Ethmoidal Infundibulum

The ethmoidal infundibulum is a funnel-shaped channel associated with the anterior part of the middle meatus.

It participates in drainage of the anterior ethmoidal region and may communicate with the frontal sinus drainage pathway depending on anatomical configuration.

Frontal Sinus Relationship

The frontal sinus drains toward the middle nasal meatus through the frontal recess and associated drainage pathway.

The exact configuration of this pathway varies among individuals because of differences in surrounding ethmoidal air cells and adjacent structures.

Maxillary Sinus Relationship

The maxillary sinus opens into the middle nasal meatus through an ostium located high on its medial wall.

The opening is associated with the region of the hiatus semilunaris, making the middle meatus an important pathway for maxillary sinus drainage.

Ethmoidal Air Cell Relationships

Anterior ethmoidal air cells generally drain into the middle meatus through the infundibular region.

Middle ethmoidal air cells commonly open on or near the ethmoidal bulla. Posterior ethmoidal air cells drain separately into the superior nasal meatus.

Ostiomeatal Complex

The region surrounding the middle meatus contains closely related pathways responsible for ventilation and drainage of several paranasal sinuses.

Clinically, these structures are often considered together as part of the ostiomeatal complex, an important functional region in paranasal sinus drainage.

Relationship to the Uncinate Process

The uncinate process is a thin, curved projection of the ethmoid bone located on the lateral wall of the nasal cavity.

It forms an important boundary of structures within the middle meatus and contributes to the anatomy of the hiatus semilunaris and ethmoidal infundibulum.

Relationship to the Superior Nasal Concha

The superior nasal concha lies above and posterior to the middle nasal concha.

The superior nasal meatus lies beneath the superior concha and receives drainage from the posterior ethmoidal air cells.

Relationship to the Inferior Nasal Concha

The inferior nasal concha lies below the middle nasal concha and forms a larger projection along the lateral nasal wall.

The inferior nasal meatus lies beneath it and receives the opening of the nasolacrimal duct.

Relationship to the Nasal Septum

The middle nasal concha projects medially toward the nasal septum but normally remains separated from it by the nasal airway.

Changes in septal position or enlargement of the concha can alter the width and pattern of airflow through this region.

Function in Nasal Airflow

The nasal conchae increase the complexity of the nasal airway and influence the distribution of inspired air.

The middle nasal concha helps direct airflow through the nasal cavity while increasing contact between inspired air and the mucosal surface.

Warming Inspired Air

The nasal mucosa has a rich vascular supply that facilitates heat exchange.

By increasing mucosal surface area and influencing airflow, the conchae contribute to warming inspired air before it reaches the lower respiratory tract.

Humidification

Moisture from the nasal mucosa humidifies inspired air.

The curved geometry of the nasal conchae increases contact between moving air and the mucosal lining, improving conditioning of inspired air.

Filtration

Particles carried in inspired air may become trapped in mucus covering the respiratory mucosa.

Ciliary activity transports mucus toward the pharynx, contributing to mucociliary clearance of inhaled particulate material.

Mucociliary Clearance

Respiratory epithelium covering much of the nasal cavity contains motile cilia.

Coordinated ciliary movement transports mucus and trapped material toward the nasopharynx, where it can be swallowed or otherwise cleared.

Blood Supply

The mucosa covering the middle nasal concha participates in the extensive arterial network of the nasal cavity.

Important arterial contributions to the lateral nasal wall arise from branches of the sphenopalatine, anterior and posterior ethmoidal, greater palatine, and facial arterial systems.

Sphenopalatine Artery

The sphenopalatine artery, a terminal branch of the maxillary artery, enters the nasal cavity through the sphenopalatine foramen.

Its lateral nasal branches provide an important part of the blood supply to the lateral wall of the nasal cavity.

Ethmoidal Arteries

The anterior and posterior ethmoidal arteries arise from the ophthalmic artery and enter the nasal region through corresponding ethmoidal canals.

They contribute to the vascular supply of superior portions of the nasal cavity and ethmoidal region.

Venous Drainage

Veins of the nasal cavity form extensive plexuses that generally accompany arterial pathways.

Venous drainage communicates with facial veins, the pterygoid venous plexus, and veins associated with the orbital and cranial regions.

Sensory Innervation

General sensation from the nasal cavity is supplied by branches of the trigeminal nerve.

The anterosuperior region receives fibers associated primarily with the ophthalmic division, while much of the posteroinferior nasal cavity receives fibers associated with the maxillary division.

Anterior Ethmoidal Nerve

The anterior ethmoidal nerve is a branch of the nasociliary nerve from the ophthalmic division of the trigeminal nerve.

Its internal nasal branches provide general sensory innervation to portions of the anterior and superior nasal cavity.

Posterior Lateral Nasal Nerves

Posterior portions of the lateral nasal wall receive general sensory fibers associated with branches of the maxillary division of the trigeminal nerve through the pterygopalatine region.

These fibers contribute to sensation from the mucosa around the conchae and meatuses.

Autonomic Innervation

Autonomic fibers regulate glandular secretion and vascular tone within the nasal mucosa.

Parasympathetic secretomotor fibers reach nasal glands through pathways associated with the facial nerve and pterygopalatine ganglion, while sympathetic fibers influence vascular smooth muscle.

Parasympathetic Supply

Preganglionic parasympathetic fibers originate from the facial nerve and travel through the greater petrosal nerve before reaching the pterygopalatine ganglion.

Postganglionic fibers are distributed with branches of the maxillary nerve to glands of the nasal mucosa.

Sympathetic Supply

Postganglionic sympathetic fibers originate from the superior cervical ganglion and travel through periarterial plexuses and the deep petrosal nerve.

They pass through the pterygopalatine region and contribute primarily to regulation of vascular tone within the nasal mucosa.

Relationship to Olfaction

The principal olfactory region is located in the superior part of the nasal cavity, particularly around the superior nasal concha, upper nasal septum, and roof.

The middle nasal concha is predominantly associated with respiratory rather than specialized olfactory mucosa, although airflow around the conchae influences delivery of odor-containing air toward the olfactory region.

Anatomical Variations

The middle nasal concha demonstrates clinically important variations in size, shape, curvature, and pneumatization.

These variations can alter the dimensions of the middle meatus and relationships among sinus drainage pathways.

Concha Bullosa

A concha bullosa is pneumatization of a nasal concha, most commonly the middle nasal concha.

The air-filled space represents extension of ethmoidal pneumatization into the turbinate and can vary considerably in size.

Clinical Significance of Concha Bullosa

A small concha bullosa may produce no symptoms.

A larger pneumatized middle concha can narrow the middle meatus or alter relationships within the ostiomeatal region, potentially affecting ventilation and drainage of nearby paranasal sinuses.

Paradoxical Middle Turbinate

The curvature of the middle nasal concha can vary.

In a paradoxical middle turbinate, the curvature is oriented differently from the usual configuration and may narrow the middle meatus when prominent.

Middle Concha and Sinus Drainage

Because the middle nasal concha forms the medial boundary of the middle meatal region, its anatomy directly influences access to and dimensions of several sinus drainage pathways.

Swelling, anatomical variation, or displacement in this region can alter ventilation and mucus clearance from associated paranasal sinuses.

Rhinosinusitis

Inflammation and mucosal swelling around the middle meatus can narrow sinus drainage pathways.

Impaired drainage and ventilation of the frontal, maxillary, or anterior ethmoidal sinuses may contribute to the anatomical and physiological processes involved in rhinosinusitis.

Endoscopic Landmark

The middle nasal concha is one of the most important landmarks during endoscopic examination of the nasal cavity.

Its identification helps orient the examiner to the middle meatus, uncinate process, ethmoidal bulla, and neighboring paranasal sinus drainage pathways.

Endoscopic Sinus Surgery

The middle turbinate is an important reference structure during functional endoscopic sinus surgery.

Knowledge of its attachment, neighboring ethmoidal structures, and anatomical variations is essential for understanding surgical orientation within the lateral nasal wall and middle meatus.

Relationship to the Skull Base

The middle nasal concha is part of the ethmoid bone, which also contributes to the anterior cranial base.

This relationship is clinically important because superior ethmoidal structures lie near the cribriform plate and anterior cranial fossa.

Relationship to the Orbit

The ethmoidal labyrinth lies between the nasal cavity medially and the orbit laterally.

The thin orbital plate of the ethmoid separates ethmoidal air cells from the orbit, making the middle meatal and ethmoidal regions closely related to orbital anatomy.

Key Anatomical Relationships

The middle nasal concha is part of the ethmoid bone.
It projects medially from the lateral wall of the nasal cavity.
The middle nasal meatus lies inferior to it.
The frontal sinus drains toward the middle meatal region.
The maxillary sinus opens into the middle nasal meatus.
Anterior and middle ethmoidal air cells are associated with drainage into the middle meatus.
The ethmoidal bulla and hiatus semilunaris are important landmarks beneath the middle concha.
The uncinate process is closely related to the middle meatal drainage pathways.
The concha is covered predominantly by respiratory mucosa.
It contributes to warming, humidification, filtration, and regulation of inspired airflow.
Its mucosa receives trigeminal sensory and autonomic innervation.
Concha bullosa is a common anatomical variation involving pneumatization of the middle turbinate.
The middle concha is an important landmark during nasal endoscopy and endoscopic sinus surgery.

Clinical Importance

The middle nasal concha is particularly important because of its close relationship to the middle nasal meatus and the drainage pathways of several paranasal sinuses. Its anatomy therefore connects the structural organization of the nasal cavity with sinus ventilation and mucociliary drainage.

Anatomical variations such as concha bullosa or altered curvature can change the dimensions of the middle meatus. Mucosal swelling in this region can also affect the narrow channels through which the frontal, maxillary, and anterior ethmoidal sinuses communicate with the nasal cavity.

Understanding the middle nasal concha provides the anatomical foundation for studying nasal airflow, the middle meatus, paranasal sinus drainage, the ostiomeatal complex, ethmoidal anatomy, rhinosinusitis, nasal endoscopy, and endoscopic sinus surgery.