External nose

The external nose is a midline protuberance in the middle of the face. Important anatomical landmarks of the external nose include:

• Nasal ridge: prominent anterior midline border of external nose, from the nasal root to the nasal tip.

• Nasal bridge: the area between two medial canthi of eyes, just beneath the glabella.

• Nasal root: the most depressed area within the nasal bridge (just underneath the glabella). It marks the commencement of nasal ridge.

• Nasal tip: the tip of external nose, which marks the termination of nasal ridge.

• Ala or wing of nose: the lateral surface of external nose, which is shaped by the alar cartilage and covers the naris.

• Nasal base: a hypothetical line interconnecting the two lateral extents of the ala or wings of nose.

• Columella: part of external nose connecting the nasal tip with the nasal base and partitioning the naris from each other.

The external nose houses the nostrils, or nares, that mark the commencement of the respiratory tract, in conjunction with the mouth. Behind the nose are the olfactory mucosa and the paranasal air sinuses.

The external nose comprises mainly of cartilage, including the major and minor alar cartilages. The septal cartilage contributes mainly to the nasal septum, however, its septal processes extend laterally to provide support to the roof of the external nose.

Remaining part of external nose is bony and is formed by the paired nasal bones, articulating with each other at the internasal suture. Laterally these are supported by the frontal and maxillary bones.

The external nose is covered over by skin with no underlying fat pads. The nasal group of muscles overlying the external nose include the nasalis muscle with its transverse compressor naris and the alar dilator naris sub-parts. The former compresses and closes the nostrils, while the latter–along with depressor septi nasi–help in opening and flaring up the nostrils.