Learning Objective: By the end of this session, the learner should be able to describe the surface anatomy, skeletal structure, muscles, blood supply, lymphatics, and innervation of the external nose and recognize key clinical correlations.
Surface Appearance
The external nose has a pyramidal shape. The nasal root is the superior attachment to the forehead, while the apex forms the rounded tip inferiorly. The dorsum spans between the root and the apex. The nares lie inferior to the apex and open into the vestibule. They are bound medially by the nasal septum and laterally by the ala nasi.
Activity:
Skeletal Structure
Bony Part (superior):
- Nasal bones
- Frontal bone
- Maxillae
Cartilaginous Part (inferior):
- 2 lateral cartilages
- 2 alar cartilages
- 1 septal cartilage
- Additional small alar cartilages
The skin over the bony part is thin; over the cartilaginous part, thick and sebaceous. Hairs in the vestibule help filter inspired air.
Clinical Relevance – Saddle Nose Deformity
Loss of septal support leads to a sunken nasal bridge.
Causes include:
- Trauma involving the septal cartilage or bone
- Septal haematoma causing cartilage necrosis due to disrupted perichondrial diffusion
Muscles of the External Nose
Small facial muscles insert into the nose and are all supplied by the facial nerve (CN VII).
- Procerus: Depresses the medial eyebrows; wrinkles the dorsum skin
- Nasalis (transverse part): Assists procerus in compression
- Nasalis (alar part): Flares the nares
- Depressor septi nasi: Assists in nares dilation
Activity:
Vessels and Lymphatics
Arterial Supply
- Maxillary artery branches
- Ophthalmic artery branches
- Facial artery branches: angular and lateral nasal artery
Venous Drainage
-
Facial vein → internal jugular vein
Lymphatics
-
Drain along vessels → deep cervical lymph nodes
Clinical Relevance – Danger Triangle of the Face
The facial vein communicates with the cavernous sinus via the ophthalmic veins.
This allows infections from the nose/upper lip region to spread intracranially → potential cavernous sinus thrombosis, meningitis, or brain abscess.
Innervation
Sensory (trigeminal nerve – CN V):
- External nasal nerve (V1): Dorsum, alae, vestibule
- Infrorbital nerve (V2): Lateral nose
Motor:
- Facial nerve (CN VII): All nasal muscles
