Nose Diagram

The nose is an organ of smell and also acts as a respiratory passage. Most receptors for smell are placed in the upper 1/3rd portion of the nasal cavity and this portion is lined by the olfactory mucosa. The remaining portions are lined by respiratory mucosa. The olfactory mucosa is thin and less vascular than the respiratory mucosa.

Here, let’s learn more about the anatomy of the nose with the help of a diagram.

Labelled Diagram of Nose

Nose – Description

In humans, the external nose has the following features:

1. An apex or tip at the lower free end.
2. The narrow upper part called the bridge or root.
3. The round border between the root and apex called the dorsum.
4. Two piriform apertures at the lower end called the nares or nostrils.
5. The lowered flared part called the ala.

• The nasal skin is very thin and is loosely attached to the underlying structures, thus it is mobile. The skin over the alae and apex is thicker and more adherent and contains large sebaceous glands.
• The upper one-third of the external nose is bony and the lower two-thirds are cartilaginous.
• The cartilaginous framework is formed by lateral cartilage, major alar cartilage and a single median septal cartilage. The major alar and lateral cartilage are also termed inferior and superior lateral cartilages respectively.
• The lateral cartilages articulate above the margin of the piriform aperture. The major alar is U-shaped cartilage that consists of the medial and lateral crus.
• The medial crura on either side meet somewhere in the middle below the lower margin of the septal cartilage to form the lower part of the nasal septum called the columella. The lateral crus also extends into the ala of the nose but does not reach the bony part. The gap is filled by minor alar cartilages and some fibrofatty tissue. These are mostly of no clinical or functional significance.
• The bony framework is formed by the following structures – two nasal bones and frontal processes of the maxillae. The two nasal bones formes the bridge of the nose.

Nasal Cavities

• The nasal septum divides the internal nose into left and right nasal cavities. Each nasal cavity communicates with the outside via the nostrils. Likewise, the cavity communicates with the nasopharynx via the choana or the posterior nasal aperture.
• Each cavity is divided into 2 — the vestibule of the nose and the nasal cavity proper. The former is a small anteroinferior portion lined by the skin and the latter is a large posterosuperior portion lined by mucosa.
• The skin of the vestibule portion contains sebaceous glands, hair follicles and interlacing hair known as the vibrissae.
• The nasal cavity forms boundaries with the roof, floor, medial and lateral wall.
• The anterior one-third of the roof slopes forwards and downwards and is formed by the nasal spine and the nasal bone. The middle third is formed by the cribriform plate of the ethmoid. The posterior third is formed by the anterior surface of the sphenoid body.
• The floor is formed by the upper surface of the hard palate and the medial wall is formed by the nasal septum. The lateral wall is formed by several bones and cartilages like the concha, nasal bone, lacrimal, major alar cartilage, etc.

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