Inferior nasal concha
|Inferior nasal concha|
|Medial wall of left orbit. (Inferior nasal concha visible in center in yellow.)|
|Figure 1: Lateral wall of right nasal cavity showing inferior concha in situ. (pink)|
|Latin||Concha nasi inferior,
concha nasalis inferior
|Articulations||ethmoid, maxilla, lacrimal, palatine|
The inferior nasal concha (inferior turbinated bone) is one of the turbinates in the nose. It extends horizontally along the lateral wall of the nasal cavity [Fig. 1] and consists of a lamina of spongy bone, curled upon itself like a scroll. Each inferior nasal concha is considered a pair of facial bones since they arise from the maxillae bones and projects horizontally into the nasal cavity. They are also termed 'inferior nasal turbinates' because they function similar to that of a turbine: 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 and superior nasal concha which arise from 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.
The medial surface is convex, perforated by numerous apertures, and traversed by longitudinal grooves for the lodgement of vessels.
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;
- the posterior with the conchal crest of the palatine;
- the middle portion presents three well-marked processes, which vary much in their size and form.
- Of these, the anterior or lacrimal process 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.
- Behind this process a broad, thin plate, the ethmoidal process, 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 inferior border is free, thick, and cellular in structure, more especially in the middle of the bone.
Both extremities are more or less pointed, the posterior being the more tapering.
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.