The nasal cavity is an irregular, bilateral air-filled space located above the roof of the oral cavity. The nasal cavity forms the internal part of the nose. It is an initial part of the respiratory tract, and it lodges the organ of olfaction.

The bony frame of the nasal cavity is formed by several bones of the skull, including:

Anteriorly, the nasal cavity opens with the nasal aperture. Posteriorly, the nasal cavity opens into the nasopharynx through a pair of oval openings called the choanae.

The nasal cavity is lined with the mucosa, and it is a part of the upper airway passage. It communicates with the paranasal sinuses, including the ethmoidal air cells and the frontal, sphenoidal and maxillary sinuses.

Walls

Each half of the bilateral nasal cavity has a roof, floor, medial and lateral walls and a vestibule:

The roof of the nasal cavity is formed by the ethmoid and sphenoid bones. The anterior slope of the roof is formed by the cribriform plate of the ethmoid bone, while the posterior slope is formed by the anterior aspect of the body of the sphenoid.
The floor of the nasal cavity is formed by the hard palate, therefore by the palatine processes of the maxillae and the horizontal plate of the palatine bone.
The medial wall of each half of the nasal cavity corresponds to the nasal septum. The bony nasal septum is formed by the vomer and the perpendicular plate of the ethmoid.
The lateral wall of the nasal cavity is formed by the nasal surface of the maxilla, perpendicular plate of the palatine bone, labyrinth of the ethmoid bone (with superior and middle nasal conchae), inferior nasal conchae, lacrimal bone, and medial plate of the pterygoid process.
The anterior wall of the nasal cavity is formed by the nasal bone and the anterior nasal aperture.
The posterior wall of the nasal cavity is formed by the body of the sphenoid and paired choanae.

Nasal conchae

There are several formations in the nasal cavity that are shaped like curved shelves of bone called conchae or conchas.

There are three nasal conchae on each lateral wall of the nasal cavity:

Superior nasal concha
Middle nasal concha
Inferior nasal concha

The superior nasal conchae and the middle nasal conchae are parts of the labyrinth of the ethmoid bone, while the inferior nasal conchae are separate bones of the skull.

Nasal meatuses

The nasal conchae project into the nasal cavity creating five pathways called nasal meatuses.

These include:

Superior nasal meatus
Middle nasal meatus
Inferior nasal meatus
Common nasal meatus
Nasopharyngeal meatus

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Nasal cavity