Inferior nasal concha bone

At a glance

English

Inferior nasal concha bone

Latin (TA2)

Concha nasalis inferior

System

Bone

Region

Head

Side

Paired, left and right

About the inferior nasal concha bone

The inferior nasal concha, or inferior turbinate, is a thin, curled plate of spongy bone that runs from front to back along the lower part of the side wall of each nasal cavity. Unlike the superior and middle conchae, which are parts of the ethmoid and so count as cranial bones, the inferior concha is a separate bone and is classed with the bones of the face. Covered with thick, highly vascular mucosa, it projects into the airway and makes the passing air swirl over a wide moist surface, where it is warmed, humidified and cleaned before reaching the lungs.

It is described by its surfaces, borders and ends. The medial surface faces the septum; it is convex, pitted with small holes and marked by grooves for vessels. Its lateral face, by contrast, is hollow and roofs the inferior meatus, the passage below the concha. The lower border hangs free, thick and spongy, especially in its middle part. Both ends taper to a point, the back one more sharply.

The upper border is thin and irregular and is the only part fixed to the wall of the nose. In front it rests on a ridge of the maxilla, the conchal crest, and behind on the matching crest of the palatine bone. In between it sends out three processes. The small, pointed lacrimal process rises to meet the lacrimal bone and the maxilla, helping to wall the nasolacrimal canal. Behind it the ethmoidal process climbs to meet the ethmoid's uncinate process, and the maxillary process curves down and outwards to cover part of the opening of the maxillary sinus.

The nasolacrimal duct opens into the inferior meatus under the front of the concha, which is why crying makes the nose run. Swelling of the mucosa over the concha is a common cause of nasal blockage in rhinitis, and the bone or its covering may be reduced surgically. The bone ossifies from a single centre in the lateral part of the cartilage capsule of the nose around the fifth fetal month.

Function and supply

Function

Increases the surface of the nasal lining so that inhaled air is warmed, moistened and filtered.

Nerve supply

Not innervated as a muscle is; the mucosa over it is supplied by posterior inferior nasal branches of the greater palatine nerve and, in front, by the anterior superior alveolar nerve.

Blood supply

Posterior lateral nasal branches of the sphenopalatine artery, with contributions from the greater palatine artery; a rich venous plexus in the mucosa swells and shrinks with the nasal cycle.