The nasal cavity is a continuation of each nostril, and it is the space which lies behind and above the nose. The cavity is divided into two by a wall of cartilage called the nasal septum. The nasal septum continues towards the back in the form of a bony structure called the bony septum made up of four different bones. Large deviations of the nasal septum sometimes result in narrowing of the nasal cavity.

The forward section of this cavity within and above each nostril is referred to as the vestibule and behind each vestibule, along the outer wall are three structures called the nasal conchae or turbinate which hang over an air passage.

Functionally, the nasal cavity has two areas. The area above the uppermost concha is called the olfactory region and it is responsible for smell. A portion of the lining contains nerve cells with projections called dendrites which dissolve microscopic particles from odour-emitting substances that chemically stimulate the olfactory nerve cells.

The rest of the nasal cavity is the respiratory area. The respiratory region is lined by mucus membrane which secretes mucus from its cells to help trap dust and other particles. Each side of the cavity is surrounded by paired sinuses called paranasal sinuses that drain into the nose.