The inferior nasal concha (inferior turbinated bone or inferior turbinal/turbinate) is one of the three paired

nasal concha In anatomy, a nasal concha (; : conchae; ; Latin for 'shell'), also called a nasal turbinate or turbinal, is a long, narrow, curled shelf of bone tissue, bone that protrudes into the breathing passage of the nose in humans and various other anim ...

e in the

nose A nose is a sensory organ and respiratory structure in vertebrates. It consists of a nasal cavity inside the head, and an external nose on the face. The external nose houses the nostrils, or nares, a pair of tubes providing airflow through the ...

. It extends horizontally along the lateral wall of the

nasal cavity The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nas ...

and consists of a

lamina Lamina may refer to: People * Saa Emerson Lamina, Sierra Leonean politician * Tamba Lamina, Sierra Leonean politician and diplomat Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathem ...

of spongy

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

, curled upon itself like a scroll, (''turbinate'' meaning inverted cone). The inferior nasal conchae are considered a pair of facial bones. As the air passes through the turbinates, the air is churned against these mucosa-lined bones in order to receive warmth, moisture and cleansing. Superior to inferior nasal concha are the

middle nasal concha The medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha (middle nasal turbinate). It is rough, ...

and

superior nasal concha The superior nasal concha is a small, curved plate of bone representing a medial bony process of the labyrinth of the ethmoid bone. The superior nasal concha forms the roof of the superior nasal meatus. Anatomy Anatomical relations The super ...

which both arise from the

ethmoid bone The ethmoid bone (; from ) is an unpaired bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. The cubical (cube-shaped) bone is lightweight due to a spongy constructi ...

, of the cranial portion of the skull. Hence, these two are considered as a part of the cranial bones. It has two surfaces, two borders, and two extremities.

Structure

Surfaces

The medial surface is

convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytop ...

, perforated by numerous apertures, and traversed by longitudinal grooves for the lodgement of vessels. The lateral surface is concave, and forms part of the inferior meatus.

Borders

Its upper border is thin, irregular, and connected to various bones along the lateral wall of the nasal cavity. It may be divided into three portions: of these, * the ''anterior'' articulates with the conchal crest of the

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

; * the ''posterior'' with the conchal crest of the

palatine A palatine or palatinus (Latin; : ''palatini''; cf. derivative spellings below) is a high-level official attached to imperial or royal courts in Europe since Roman Empire, Roman times.

; * the ''middle'' portion presents three well-marked processes, which vary much in their size and form. ** Of these, the anterior or

lacrimal process The term Lacrimal or lachrymal, may refer to: Anatomy * Lacrimal apparatus * Lacrimal artery * Lacrimal bone * Lacrimal canaliculi (singular: canaliculus), also known as ''Lacrimal ducts'' * Lacrimal fossa (disambiguation) * Lacrimal fluid, see ...

is small and pointed and is situated at the junction of the anterior fourth with the posterior three-fourths of the bone: it articulates, by its apex, with the descending process of the lacrimal bone, and, by its margins, with the groove on the back of the frontal process of the maxilla, and thus assists in forming the canal for the

nasolacrimal duct The nasolacrimal duct (also called the tear duct) carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. ...

. ** Behind this process a broad, thin plate, the

ethmoidal process Behind the lacrimal process of the inferior nasal conchae lies a broad, thin plate, the ethmoidal process, which ascends to join the uncinate process of the ethmoid; from its lower border a thin lamina, the maxillary process, curves downward a ...

, ascends to join the uncinate process of the ethmoid; from its lower border a thin lamina, the maxillary process, curves downward and lateralward; it articulates with the maxilla and forms a part of the medial wall of the

maxillary sinus The pyramid-shaped maxillary sinus (or antrum of Nathaniel Highmore (surgeon), Highmore) is the largest of the paranasal sinuses, located in the maxilla. It drains into the middle meatus of the noseHuman Anatomy, Jacobs, Elsevier, 2008, page 209- ...

. The inferior border is free, thick, and cellular in structure, more especially in the middle of the bone.

Extremities

Both extremities are more or less pointed, the posterior being the more tapering.

Development

The inferior nasal concha is ossified from a single center, which appears about the fifth month of fetal life in the lateral wall of the cartilaginous nasal capsule. The entire inferior concha may be absent in some people. This is a consequence of embryologic

agenesis In medicine, agenesis () refers to the failure of an organ to develop during embryonic growth and development due to the absence of primordial tissue. Many forms of agenesis are referred to by individual names, depending on the organ affected: ...

and is a normal anatomic variant.

Clinical significance

Dysfunction

Large, swollen inferior turbinates may lead to blockage of nasal breathing.

Allergies Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...

, exposure to environmental irritants, or a persistent

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

within the sinuses can lead to turbinate swelling. Deformity of the

nasal septum The nasal septum () separates the left and right airways of the Human nose, nasal cavity, dividing the two nostrils. It is Depression (kinesiology), depressed by the depressor septi nasi muscle. Structure The fleshy external end of the nasal s ...

can also result in enlarged turbinates. Treatment of the underlying allergy or irritant may reduce turbinate swelling. In cases that do not resolve, or for treatment of

deviated septum Nasal septum deviation is a physical disorder of the nose, involving a displacement of the nasal septum. Some displacement is common, affecting 80% of people, mostly without their knowledge. Signs and symptoms The nasal septum is the bone and ...

, turbinate surgery may be required.

Surgery

Inferior turbinate reduction is a surgery to reduce the size of the inferior turbinates. There are different techniques, including bipolar

radiofrequency ablation Radiofrequency ablation (RFA), also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor, sensory nerves or a dysfunctional tissue is ablated using the heat generated from medium fre ...

(also known as somnoplasty), electrocautery, and use of cold steel instruments (eg, microdebrider). Inferior turbinectomy is a surgery to remove the inferior turbinates. In the case of turbinate reduction, only small amounts of turbinate tissue are removed because the turbinates are essential for respiration. Turbinectomy is usually reserved for patients who have persistent symptoms despite previous turbinate reduction surgery. Risks of reduction of the inferior or middle turbinates include empty nose syndrome.

Additional images

File:Gray171.png, Right inferior nasal concha. Medial surface. File:Gray172.png, Right inferior nasal concha. Lateral surface. File:Slide2hal.JPG, Human skull. Inferior nasal concha.

References

External links

* * {{Authority control Bones of the head and neck Otorhinolaryngology