Middle Nasal Concha

What Is the Middle Nasal Concha?

The middle nasal concha is the curved shelf of bone that lies, as its name suggests, between the superior nasal concha above and the inferior nasal concha below on the lateral wall of each nasal cavity. Covered by mucous membrane, it is also called the middle turbinate, and it is one of the three pairs of nasal conchae.

Is the middle nasal concha a separate bone?

No. The middle nasal concha is part of the ethmoid bone, not an individual bone. It is a thin, curled plate that hangs from the medial surface of the ethmoidal labyrinth (lateral mass), forming the lower edge of that surface. Because the ethmoid is a cranial bone, the middle concha is not a facial bone; of the three conchae, only the inferior one is a separate facial bone. In Latin it is the concha nasalis media.

Explained simply

Picture a curved awning fixed to a wall above a doorway. The middle concha is that awning, and under it lie the small doorways through which three of the four pairs of sinuses empty into the nose. Air rushing past is deflected by the awning, so the doorways stay sheltered while mucus from the sinuses drains out freely.

Where Is the Middle Nasal Concha Located?

The middle nasal concha is located on the lateral wall of each nasal cavity, below and in front of the superior concha and above the inferior concha, with its free curved border hanging down toward the middle of the cavity. Its front end lies in the front part of the lateral wall, and its back end reaches toward the choanae, the openings into the nasopharynx.

Neighbors of the middle concha

• Above: the superior meatus and the superior concha.
• Below and lateral: the middle meatus, the curved air passage under its free border.
• Below: the inferior concha.
• Medially: the nasal septum, formed above by the perpendicular plate of the ethmoid bone.
• Laterally, beyond the wall: the ethmoidal air cells and, lower down, the maxillary sinus.

Anterior and posterior views

In an anterior view of the skull, the middle concha is the curved bony ridge visible in the upper half of the nasal opening on each side of the septum, with the larger inferior concha below it. From behind, through the choanae, its rounded back end can be seen above the inferior concha. Unlike the superior concha, the front end of the middle turbinate can sometimes be seen in a living person by looking into the nostril with a light.

Middle Nasal Concha Anatomy: Attachments and Lining

The middle nasal concha is a thin plate of the ethmoid bone with a rough, grooved surface, attached above to the ethmoidal labyrinth and the skull base, and free below where its curved border overhangs the middle meatus. Its attachment twists along its length, which makes it an important landmark for surgeons.

How the middle concha is attached

• Front part: attaches almost vertically to the skull base at the side of the cribriform plate, and its front end joins the ethmoidal crest on the frontal process of the maxilla.
• Middle part: turns sideways as a thin sheet, the basal (ground) lamella, which runs across to the lamina papyracea, the paper-thin inner wall of the eye socket. This sheet divides the ethmoidal air cells into an anterior group and a posterior group.
• Back part: runs nearly horizontally along the lateral nasal wall and joins the ethmoidal crest of the perpendicular plate of the palatine bone.

Surface, lining and supply

The upper part of the medial surface of the ethmoidal labyrinth is marked by grooves that hold branches of the olfactory nerves on their way to the mucous membrane over the superior concha. The middle concha itself is covered mainly by respiratory mucosa: ciliated pseudostratified columnar epithelium with goblet cells, over a lamina propria with glands and a venous plexus that can swell, though less than over the inferior concha. In some people, olfactory epithelium extends onto the upper part of its medial surface. Blood comes mostly from posterior lateral nasal branches of the sphenopalatine artery, with help from the anterior ethmoidal artery, and sensation is carried by branches of the maxillary nerve and the anterior ethmoidal nerve.

Middle Nasal Concha and Meatus: What Drains There?

The middle meatus, the passage directly under the middle nasal concha, receives the drainage of the frontal sinus, the maxillary sinus and the anterior ethmoidal cells, which makes it the busiest drainage area in the nose. Lifting the middle concha out of the way, as a surgeon does with an endoscope, reveals several structures on the lateral wall:

• Ethmoidal bulla: a rounded bulge formed by ethmoidal air cells; the middle ethmoidal cells usually open on or above it.
• Uncinate process: a thin, hook-shaped plate of the ethmoid bone curving below and in front of the bulla.
• Semilunar hiatus: the crescent-shaped gap between the bulla and the uncinate process.
• Ethmoidal infundibulum: a funnel-shaped channel behind the hiatus into which the maxillary sinus opening and many anterior ethmoidal cells drain.

The frontal sinus drains downward through the frontal recess at the front of the middle meatus. Together these openings form the ostiomeatal complex, and our paranasal sinuses and nasal meatus pages follow each drainage route in more detail.

What Does the Middle Nasal Concha Do?

The middle nasal concha shields the sinus openings in the middle meatus from the direct, pressurized airflow of each breath, and it helps warm, moisten, filter and direct the air flowing through the nose.

Function of the middle nasal concha

• Protecting the sinuses: by overhanging the middle meatus, the thin bone keeps the fast airstream from striking the openings of the maxillary, frontal and ethmoid sinuses, so their mucus can drain steadily.
• Guiding airflow: much of the air inhaled during each breath passes through the region between the middle and inferior turbinates and through the middle meatus, and the shape of the middle concha helps split and slow that stream.
• Conditioning air: its moist, blood-rich lining adds heat and water vapor, working together with the larger inferior concha.
• Filtering: particles caught in its mucus are swept back by cilia toward the pharynx and swallowed.
• Helping smell: by directing part of the airflow upward and, in some people, carrying a little olfactory lining on its upper surface.

Function of the superior and middle nasal conchae together

The two ethmoidal conchae split the work. The superior concha is mainly a smell surface over the posterior ethmoidal drainage, while the middle concha guards the much larger drainage area of the frontal, maxillary and anterior ethmoid sinuses. Together they make the lateral wall a series of sheltered pockets rather than a flat surface. This conditioning of air is part of the wider respiratory system functions of the upper airway.

Middle Nasal Concha vs Superior and Inferior Nasal Concha

The middle nasal concha is larger than the superior concha and smaller than the inferior concha, shares the ethmoid bone with the superior concha, and differs from the inferior concha, which is a separate facial bone. The table below compares the three side by side.

Two other structures are often confused with it. The perpendicular plate of the ethmoid bone is a flat midline sheet that forms the upper part of the nasal septum, while the middle concha hangs from the side of the same bone and curls toward that septum. The palatine bone is a separate bone at the back of the nasal cavity, and its ethmoidal crest is simply where the back end of the middle concha attaches.

How Does the Middle Nasal Concha Develop?

The middle nasal concha develops before birth from one of the ethmoturbinals, ridges on the side wall of the cartilaginous nasal capsule, and it ossifies with the ethmoidal labyrinth, whose ossification center appears around the fourth to fifth month of fetal life. The ethmoidal air cells grow into the surrounding bone after birth and through childhood, which is how air cells can come to invade the middle concha itself.

Common variants of the middle concha

• Concha bullosa: an air-filled cell inside the middle concha, formed when an ethmoidal air cell grows into it. It is one of the most common variants seen on sinus CT scans and may affect one or both sides.
• Paradoxical middle turbinate: a middle concha that curves outward, toward the lateral wall, instead of inward toward the septum, which can narrow the middle meatus.
• Bifid or lobulated middle concha: a concha with a groove or split along its lower edge.

Most of these variants cause no symptoms and are found by chance on imaging. In later life, the nasal lining over the middle concha, like the rest of the nose, tends to become thinner and drier.

Common Conditions That Affect the Middle Nasal Concha

Most problems linked to the middle nasal concha involve the middle meatus beneath it, because swelling or a change in shape there can block the sinus openings. Our respiratory diseases section covers related conditions, and a long-lasting blocked nose or facial pressure is a reason to see a doctor.

• Symptomatic concha bullosa: a large air cell can crowd the middle meatus, press on the septum, or itself become inflamed, sometimes contributing to nasal blockage or sinus problems.
• Chronic rhinosinusitis: long-term inflammation of the sinuses, often linked with swelling around the ostiomeatal complex under the middle concha.
• Nasal polyps: soft, pale growths that usually arise from the ethmoid region and bulge into the middle meatus, sometimes reaching the nasal cavity below.
• Septal contact: a deviated septum can touch the middle concha and narrow the airway.

Because its front part attaches to the skull base beside the thin cribriform plate, the middle concha is a key landmark in endoscopic sinus surgery, and surgeons work carefully around this attachment.