Anatomy of the nasal cavity

The nose is the initial part of the airways of the respiratory system and consists of two main parts: the external nose and the nasal cavity.

The nasal cavity (cavitas nasi) is a part of the upper respiratory airways containing the olfactory organ.

It is represented by the right and left halves separated by the nasal septum (septum nasi). A half of the nasal cavity has five walls: superior, inferior, posterior, medial and lateral.

The nasal cavity communicates with the external environment through a specific aperture of the skull, which is called the piriform aperture (apertura piriformis). It is formed by nasal notches of the maxilla and nasal bones.

The nasal cavity consists of the vestibule and the proper nasal cavity.

Nasal vestibule (vestibulum nasi)

This is a small area that is delimited by the limen nasi (limen nasi)

From the inside, the nasal vestibule is a continuation of the skin of the external nose and contains sebaceous and sweat glands, as well as short, stiff hairs called vibrissae.

From behind, through the posterior nasal apertures or choanae (choanae), it continues into the nasopharynx.

Walls of the nasal cavity and structures that form them

The nasal septum is the medial wall of each nasal cavity and consists of three parts:

Bony part (pars ossea)

Which is formed by the perpendicular plate of the ethmoid bone and the vomer, as well as the nasal crests of the palatine bone and the maxilla

Cartilaginous part (pars cartilaginea). It is an unpaired septal nasal cartilage.

Membranous part (pars membranacea), which is located in the anterior part of the nose and is the thinnest and most mobile component of the nasal septum.

The superior wall of the nasal cavity, which is formed by a small part of the frontal bone, cribriform plate of the ethmoid bone (lamina cribrosa) and partly by the sphenoid bone.

Cribriform plate решетчатой кости (lamina cribrosa)

The posterior wall of the nasal cavity is a short and located in the superior part above the choanae. It is formed by the nasal surface of the body of the sphenoid bone with a paired opening of the sphenoid sinus (apertura sinus sphenoidalis) present on it.

Opening of the sphenoid sinus (apertura sinus sphenoidalis)

The inferior wall of the nasal cavity, or its floor, includes the palatine process of the maxilla (processus palatinus maxillae);

and the horizontal plate of the palatine bone (lamina horizontalis ossis palatini);

Horizontal plate of the palatine bone (lamina horiontalis ossis palatini)

which form the hard palate (palatum osseum).

The floor of the nasal cavity is the “roof” of the oral cavity.

The lateral wall of the nasal cavity is formed by the lacrimal bone (os lacrimale);

and the orbital plate of the ethmoid bone (lamina orbitalis);

which separate the nasal cavity from the orbit, as well as the nasal surface of the frontal process of the maxilla (processus frontalis);

and its thin bony plate, which separates the nasal cavity and the maxillary sinus (sinus maxillaris).

On the lateral wall of the nasal cavity, three nasal conchae hang inside:

1. Superior nasal concha (concha nasalis superior)

2. Middle nasal concha (concha nasalis media)

3. Inferior nasal concha (concha nasalis inferior)

4. Sometimes there is the supreme nasal concha (conchae nasales suprema) above the superior nasal concha

The nasal meatuses are located between the nasal chonchae:

1. Superior nasal meatus (meatus nasi superior)

Which is connected to the sphenoidal sinus and the posterior ethmoidal cell

2. Middle nasal meatus (meatus nasi medius)

Which communicates with:

1. Frontal sinus through the ethmoidal infundibulum (infundibulum ethmoidale),

2. Maxillary sinus through the hiatus semilunaris (hiatus semilunaris)

3. Maxillary sinus through the hiatus semilunaris (hiatus semilunaris)

These cells form protrusions towards the nasal concha, the so-called ethmoidal bulla (bulla ethmoidalis)

3. Inferior nasal meatus (meatus nasi inferior)

It communicates with the nasolacrimal canal.

Nasolacrimal canal (meatus nasi inferior)

4. Common nasal meatus (meatus nasi communis) passes between the medial surfaces of the nasal conchae

Nasal mucosa

Nasal mucosa (tunica mucosa nasi), in addition to warming and moving air, performs an olfactory function. Therefore, two regions are distinguished in it:

Olfactory region (regio olfactoria) is the mucous membrane covering the right and left superior nasal conchae and part of the middle nasal conchae, as well as the superior part of the nasal septum. It contains olfactory receptors.
Respiratory region (regio respiratoria) includes the rest of the mucous membrane. In the area of the inferior concha, there is a large number of venous plexuses that warm the inhaled air.

Blood supply

The following arteries supply the nasal cavity with blood:

Branches of the sphenopalatine artery (rr. sphenopalatinae), which in turn branches from the maxillary artery (a. maxillaris)
Branches of the sphenopalatine artery (rr. sphenopalatinae), which in turn branches from the maxillary artery (a. maxillaris)

Venous drainage

Venous drainage is carried out through the sphenopalatine vein (v. sphenopalatina), which flows into the pterygoid plexus (plexus pterygoideus)

Lymphatic drainage

Lymph drains from the nasal cavity through the lymphatic vessels and goes to the submandibular and submental lymph nodes.

Innervation

The nasal cavity is innervated as follows:

The anterior part of the nasal cavity is innervated by the branches of the anterior ethmoidal nerve, which is a continuation of the nasociliary nerve.
The posterior part of the nasal cavity is innervated by the branches of the nasopalatine nerve and the posterior branches of the maxillary nerve.
The glands of the nasal cavity are innervated by the pterygopalatine ganglion and the vegetative nucleus of the intermediate nerve.

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