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External Nose

Nasus externus

For medical students2 min readUpdated 2026-10-10

The external nose (nasus externus) is the initial segment of the human respiratory system. It is located in the corresponding region of the face and visually resembles a triangular pyramid, the external surface of which is entirely covered by skin.

SystemThe initial segment of the human respiratory system
TopographyOccupies a specific facial region — regio nasalis
ShapeAnatomically resembles a three-sided pyramid
CoveringExternally, all structures are tightly covered by skin
ConnectionsCartilages and bones are interconnected by fibrous tissue

External Structure and Topography

Anatomically, the organ forms the relief of the central part of the face, occupying the designated nasal region — regio nasalis. In terms of spatial geometry, its shape is closest to a triangular pyramid. The entire outer surface of the structure is covered by skin.

In macroscopic structure, four key components smoothly transitioning into each other are distinguished:

The basis for forming the dorsum consists of both bony elements (nasal bones) and a complex cartilage complex, which includes the lateral cartilages, septal cartilage, and alar cartilages.

Lateral Nasal Cartilage

The base of the lateral slopes is formed by the lateral nasal cartilage (cartilago nasi lateralis). This is a paired structure whose contours resemble an irregular triangle.

This structure plays a crucial biomechanical role: it directly participates in forming the dorsum and also partially captures the alar region. Topographically, the lateral cartilage closely adheres to the nasal bone. Along the midline, it forms a strong connection with the corresponding cartilage of the opposite side and also fuses with the nasal septal cartilage, creating a unified supporting framework for the upper part of the organ.

Greater Alar Cartilage

The lower part of the cartilaginous skeleton is represented by the greater alar cartilage (cartilago alaris major). This is a paired anatomical element whose function is to form the entrance to the respiratory tract — it surrounds the nostrils anteriorly, laterally, and from the inner surface.

Structurally, the greater cartilage is divided into two crura:

  1. Medial crus (crus mediale) — the internal element. These paired crura serve as a natural barrier separating the right and left nostrils from each other. The anteroinferior edge of the septal cartilage wedges tightly right between them.
  2. Lateral crus (crus laterale) — the external element. It is significantly wider and longer than its medial counterpart. This specific anatomical structure acts as the main cartilaginous skeleton for the ala of the nose.

Minor and Accessory Cartilages

Additionally, lesser alar cartilages (cartilagines alares minores) adjoin the lateral crus of the greater cartilage. Topographically, they are located in the posterosuperior regions of the nasal ala, supplementing the supporting contour.

In some cases, the anatomical picture may be augmented by the presence of accessory nasal cartilages — cartilagines nasi accessoriae.

It is important to note that absolutely all cartilages forming the skeleton are covered externally by a specialized membrane — the perichondrium (perichondrium). To ensure the structural integrity of the entire complex, the cartilages are securely fastened both to each other and to the adjacent bones of the facial skeleton via dense fibrous tissue.

Frequently asked questions

Which skull bones participate in forming the bony skeleton of the external nose?

The bony skeleton of the external nose is formed by the nasal bones, frontal processes of the maxilla, and the nasal process of the frontal bone.

  • Nasal bones (ossa nasalia) — paired bones forming the nasal dorsum and determining its shape.
  • Maxilla (maxilla) — its frontal processes form the lateral slopes (lateral boundaries) of the nose.
  • Frontal bone (os frontale) — its nasal process articulates with the nasal bones, forming the upper boundary of the bony region.
Which arteries provide the blood supply to the external nose?

The blood supply to the external nose is derived from branches of the facial, ophthalmic, and infraorbital arteries.

  • Facial artery (a. facialis) — gives off branches to the external nose, including the angular artery (a. angularis).
  • Ophthalmic artery (a. ophthalmica) — participates in blood supply via the dorsal nasal artery (a. dorsalis nasi), which supplies the nasal dorsum.
  • Infraorbital artery (a. infraorbitalis) — forms anastomoses with branches of the facial artery.

An important anastomosis connecting the internal and external carotid artery systems is formed between the dorsal nasal artery and the angular artery.

Which nerves provide sensory innervation to the skin of the external nose?

Sensory innervation to the skin of the external nose is provided by branches of the ophthalmic and maxillary nerves (CN V1 and CN V2).

  • Infratrochlear nerve (n. infratrochlearis) — innervates the skin of the nasal root.
  • Anterior ethmoidal nerve (n. ethmoidalis anterior) — gives off external nasal branches (rr. nasales externi) innervating the dorsum, alae, and tip of the nose.
  • Infraorbital nerve (n. infraorbitalis) — gives off external nasal branches providing sensation to the skin of the lateral surface of the nose.
Into which lymph nodes does lymph drainage from the external nose occur?

Lymph drainage from the external nose occurs into the submandibular and superficial parotid lymph nodes.

  • Submandibular lymph nodes (nodi lymphoidei submandibulares) — receive lymphatic vessels from the external nose and nostrils.
  • Superficial parotid nodes (nodi parotidei superficiales) — receive lymph from the external nose as part of the anterior group of superficial lymphatic vessels.
Which part of the respiratory system does the external nose belong to?

The external nose is the initial segment of the human respiratory system.

Which structures form the dorsum of the nose?

The dorsum of the nose is formed by the nasal bones, lateral nasal cartilages, septal cartilage, and alar cartilages.

What separates the nostrils from each other?

The nostrils are separated from each other by the medial crura of the greater alar cartilages, between which wedges the anteroinferior edge of the septal cartilage.

Which part of the greater alar cartilage forms its main skeleton?

The main cartilaginous skeleton of the nasal ala is the lateral crus of the greater alar cartilage, as it is wider and longer than the medial crus.

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