Vasculature and Innervation of Nose

The arterial supply of the medial and lateral walls of the nasal cavity is from five sources:

1. Anterior ethmoidal artery (from the ophthalmic artery).

2. Posterior ethmoidal artery (from the ophthalmic artery).

3. Sphenopalatine artery (from the maxillary artery).

4. Greater palatine artery (from the maxillary artery).

5. Septal branch of the superior labial artery (from the facial artery).

The first three arteries divide into lateral and medial (septal) branches. The greater palatine artery reaches the septum via the incisive canal through the anterior hard palate. The anterior part of the nasal septum is the site of an anastomotic arterial plexus involving all five arteries supplying the septum (Kiesselbach area). The external nose also receives blood from first and fifth arteries listed, plus nasal branches of the infraorbital artery and the lateral nasal branches of the facial artery.

A rich submucosal venous plexus, deep to the nasal mucosa, provides venous drainage of the nose via the sphenopalatine, facial, and ophthalmic veins. The plexus is an important part of the body's thermoregulatory system, exchanging heat and warming air before it enters the lungs. Venous blood from the external nose drains mostly into the facial vein via the angular and lateral nasal veins. However, recall that it lies within the “danger area” of the face because of communications with the cavernous (dural venous) sinus.

Regarding its nerve supply of the nose, the nasal mucosa can be divided into postero-inferior and anterosuperior portions by an oblique line passing approximately through the anterior nasal spine and the spheno-ethmoidal recess. The nerve supply of the postero-inferior portion of the nasal mucosa is chiefly from the maxillary nerve, by way of the nasopalatine nerve to the nasal septum, and posterior superior lateral nasal and inferior lateral nasal branches of the greater palatine nerve to the lateral wall. The nerve supply of the anterosuperior portion is from the ophthalmic nerve (CN V₁) by way of the anterior and posterior ethmoidal nerves, branches of the nasociliary nerve. Most of the external nose (dorsum and apex) is also supplied by CN V₁ (via the infratrochlear nerve and the external nasal branch of the anterior ethmoidal nerve), but the alae of the nose are supplied by the nasal branches of the infra-orbital nerve (CN V₂). The olfactory nerves, concerned with smell, arise from cells in the olfactory epithelium in the superior part of the lateral and septal walls of the nasal cavity. The central processes of these cells (forming the olfactory nerve) pass through the cribriform plate and end in the olfactory bulb, the rostral expansion of the olfactory tract.