Nasal Cavity, Sinuses and Ear - LO 8

Nasal Walls [14:48]

8. What are the conchae and meatuses of the lateral nasal wall? What spaces communicate via each meatus?

The superior and middle nasal conchae (turbinates) are scroll-shaped components of the ethmoid bone located on the lateral wall of the nasal cavity. The superior nasal concha is the smallest with the middle concha of intermediate size. The inferior nasal concha is the largest and most substantial of the nasal conchae, and are not components of another bone. Occasionally, there are highest (supreme) nasal conchae, within the sphenoethmoidal recess. The nasal conchae are thickly lined with nasal mucosa, and serve several functions: increase surface area of nasal cavity, humidification and filtration of inspired air, and direction of airflow.

There are four meatuses or recesses associated with the nasal conchae, the:

The spheno-ethmoidal recess is located above the superior nasal concha, and the opening of the sphenoidal sinus is located here.

The superior nasal meatus is located between the superior and middle nasal conchae. The openings of the posterior ethmoidal cells are located in the superior nasal meatus.

The middle nasal meatus is located between the middle and inferior nasal conchae. The openings of several sinuses are found in the middle nasal meatus (middle ethmoidal cells, frontal sinus, maxillary sinus, and anterior ethmoidal cells).

Within the middle nasal meatus, there are several important structures. The ethmoidal bulla is a noticeable projection just inferior to the middle nasal concha, caused by the middle ethmoidal cells. Inferior to the bulla is a slit-like opening, the semilunar hiatus. The anterosuperior portion of the semilunar hiatus expands into a funnel-shaped opening, the ethmoidal infundibulum. The frontonasal duct of the frontal sinus typically drains into the ethmoidal infundibulum, while the semilunar hiatus hosts openings for the anterior ethmoidal cells and maxillary sinus.

The inferior nasal meatus can be identified below the inferior nasal concha, and contains the opening of nasolacrimal duct, which conducts tears from the orbit.