Nasal cavity

Last revised by Craig Hacking on 3 May 2023

The nasal cavity, also known as the nasal fossa, forms part of the upper respiratory tract.

Somewhat confusingly, the nasal cavity may refer to either the space either side of the nasal septum or the two spaces combined. So for the same individual one can correctly refer to their single nasal cavity and their left and right nasal cavities.

The definition of the nasal fossae is used by most as a synonym for the nasal cavity. However, in a well-known medical dictionary, the fossa is defined as that part of the nasal cavity lying anterior to the middle meatus 11.

The nasal cavity is formed by 1:

In the midline, the nasal cavity is divided into right and left halves by the nasal septum composed of fibrocartilage anteriorly and the vomer and the perpendicular plate of the ethmoid bone posteriorly and inferiorly. 

Anterior most, lies a small dilated portion, the nasal vestibule, which lies between the nasal aperture and the anterior nares, and posteriorly it is continuous with the nasopharynx via the posterior choanae. Laterally, the three nasal conchae form the three nasal meati.

The arterial supply of the nasal cavity is rich and derives from both the internal and external carotid arteries 4,5,10:

Rich arterial supply results in two anastomotic areas, which are common sites of epistaxis 4:

  • Woodruff area: anastomosis of sphenopalatine and pharyngeal arteries in the inferior lateral nasal wall, posterior to the inferior turbinate
  • Kiesselbach plexus: anastomosis of the anterior ethmoid, greater palatine, sphenopalatine and superior labial arteries in the anteroinferior nasal septum (see article on Kiesselbach plexus)

A rich submucosal venous network is formed by veins that accompany arteries. It should be noted that the posterior ethmoid veins anastomose with veins of the dura mater and orbit, making this a potential route of spread of infection. There is also an anastomosis with veins of the external nose 6.

  • anterior drainage: to the external nose 6
  • posterior drainage: via separate pathways to the lateral pharyngeal lymph nodes or deep cervical chain 6

The olfactory nerve (CN I) supplies the special sensation of smell to the olfactory epithelium in the roof of the nasal cavity, with fibers passing upwards through the cribriform plate to the olfactory bulb.

Mucosal somatic sensation of the nasal cavity is derived from numerous nerves, but in general terms the branches of the ophthalmic division of the trigeminal nerve (CN Va) supply the anterosuperior half whereas branches of the maxillary division of the trigeminal nerve (CN Vb) supply the posteroinferior half. More specifically:

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