Human Anatomy
Cavity of the Nose
Nasal cavity anatomy for MBBS: septum, conchae and meatuses, paranasal sinus drainage, Little's area and nerve supply, mapped to NMC codes AN37.1 to AN37.3.
MedNext Academy | 3 min read
Cavity of the Nose
Nasal cavity anatomy for MBBS: septum, conchae and meatuses, paranasal sinus drainage, Little's area and nerve supply, mapped to NMC codes AN37.1 to AN37.3.
The cavity of the nose chapter covers the septum, the lateral wall with its conchae and meatuses, the drainage of the paranasal sinuses and the blood and nerve supply. It grounds the anatomy of epistaxis, sinusitis and cerebrospinal fluid rhinorrhoea.
High-yield: Cavity of the Nose
- The nasal cavity is divided into two halves by the nasal septum and opens in front at the nostrils and behind at the choanae.
- The nasal septum is formed by the septal cartilage in front, the perpendicular plate of the ethmoid above and the vomer below.
- The lateral wall carries three curved conchae, superior, middle and inferior, which increase the surface for warming and moistening air.
- The space below each concha is a meatus, and most paranasal sinuses open into the middle meatus.
- The maxillary, frontal and anterior ethmoidal sinuses drain into the middle meatus through the semilunar hiatus.
- The nasolacrimal duct opens into the inferior meatus, carrying tears from the eye to the nose.
- The sphenoethmoidal recess above the superior concha receives the opening of the sphenoidal sinus.
- The upper part of the nasal cavity is lined by olfactory mucosa supplied by the olfactory nerves through the cribriform plate.
- Little's area on the anterior septum is a rich anastomosis of vessels and the usual site of nosebleeds.
- The vessels meeting in Little's area include branches of the sphenopalatine, greater palatine, anterior ethmoidal and facial arteries, called Kiesselbach's plexus.
- The maxillary sinus opening is high on its medial wall, so it drains poorly and is prone to infection.
- General sensation of the nasal cavity is carried by branches of the ophthalmic and maxillary divisions of the trigeminal nerve.
- The pterygopalatine ganglion supplies secretomotor fibres to the nasal glands, producing nasal secretions.
- Because the roof is thin at the cribriform plate, a fracture there can leak cerebrospinal fluid into the nose.
Where each sinus and duct drains
- **Middle meatus:** Maxillary, frontal and anterior ethmoidal sinuses drain here through the semilunar hiatus.
- **Inferior meatus:** Nasolacrimal duct opens here, carrying tears from the eye.
- **Superior meatus:** Posterior ethmoidal sinuses drain here.
- **Little's area:** Anterior septal anastomosis, the usual site of nosebleeds.
NMC competencies in this chapter
- **AN37.1:** Boundaries, septum and lateral wall of the nasal cavity
- **AN37.2:** Paranasal sinuses: openings, drainage and applied anatomy
- **AN37.3:** Blood supply, nerve supply and applied anatomy of the nose
Frequently Asked Questions
Where do most nosebleeds arise?
From Little's area on the anterior part of the nasal septum, where several arteries anastomose in Kiesselbach's plexus, making it a fragile and easily traumatised site.
Why does the maxillary sinus become infected easily?
Its opening lies high on the medial wall, so the sinus drains against gravity and secretions tend to stagnate, favouring infection.
Where does the nasolacrimal duct open?
It opens into the inferior meatus, below the inferior concha, which is why tears reach the nose and a blocked duct causes a watery eye.
How does this chapter help in NEET-PG?
Sinus drainage, epistaxis and the olfactory pathway are common ENT and forensic topics, so nasal anatomy is high-yield well beyond the first year.
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