The Nasal Cavity: Parts, Function, and Diseases

What is the nasal cavity? The nasal cavity (comprising the nasal passages) is an essential passage of the upper respiratory tract. It is divided into right and left divisions by the nasal septum, a cartilaginous structure.

Each half opens onto the face via the nare and communicates behind with the nasopharynx through the choanae.

Most people find it difficult to sleep during episodes of nasal congestion associated with upper airway infections. This is just one example of why nasal breathing is vital for sleep quality and respiratory health.

Nose and pharynx abnormalities can cause and even intensify sleep apnea.

In this article, you will learn what the nasal cavity is, how the nasal cavity impacts sleep apnea, and sleep apnea treatment for a better night’s sleep.

The Parts of the Nasal Cavity

There are 3 regions within each nasal cavity: the respiratory region (also known as the nasal fossa), the olfactory region, and the nasal vestibule.

Surrounding the nasal cavity are the frontal sinuses or superior anterior, ethmoid sinuses, paired maxillary sinuses, and sphenoid sinuses.


SOURCE: Encyclopædia Britannica, 2012. Retrieved from

Respiratory Region

The respiratory area controls airflow through your nose via blood level regulation in the tissues of the anterior septum and inferior turbinate.

The respiratory region is the largest area of the nasal cavity, complete with a healthy amount of mucous cells, respiratory epithelium, and blood vessels.

Olfactory Region

The olfactory region is inside the skull. This small part contains or regulates olfactory cells and receptors. Olfaction (smelling) requires nasal airflow to transport odor particles to the top of the nasal cavity where the olfactory epithelium resides.

Odor particles get stuck in olfactory mucus, and certain proteins bind to the odorants, increasing solubility.

The particles interact with olfactory receptors on cilia which send specific signals up the cribriform plate to synapse with olfactory bulb neurons. The olfactory nerve then sends signals to secondary neurons for further processing before entering the brain.

Olfactory receptors are unique in the sense that a single receptor cell can only expose one odorant type.

Nasal Vestibule

The first part of your nasal vestibule is covered with keratinized stratified squamous epithelium. The second part is covered by pseudostratified ciliated columnar epithelium.

The floor of the nasal cavity is formed by your hard palate.

The Roof of the Nasal Cavity

“The nasal cavity’s roof accommodates [two] perforations that engage with the cribriform plate,” according to this research piece.

The olfactory nerve fibers exist along those 2 accommodated perforations:

  • Anterior: the spine of the frontal and nasal bone
  • Posterior: one of the ethmoid’s cribriform plate

The Floor of the Nasal Cavity

The nasal cavity’s floor is wider than the nasal cavity’s roof.

  • Anterior: the palatine process of the maxilla
  • Posterior: a horizontal plate of the palatine bone

Agger Nasi Cells

The section closest to the front of the anterior ethmoid air cells is these Agger Nasi cells.

They form the anterior part of the frontal recess. They are both anterior and superior to the middle turbinate’s basal lamella.

Uncinate Process of the Ethmoid

The ethmoid bone includes a narrow crescent-shaped bone, called the uncinate process. It is anteriorly linked to the lacrimal bone and posterior/inferior to the ethmoid labyrinth.

This structure shields the sinuses of the infundibulum from breathing in external particles, such as smoke and pollen.


Anatomy defines a meatus as a “natural body passage.” Here are the 3 meatuses of the nasal cavity:

  • Inferior Meatus: the area between the nasal cavity floor and the inferior turbinate
  • Middle Meatus: the passageway that exists beside the inferior meatus
  • Superior Meatus: the top-most nasal passageway past the middle meatus

Sphenopalatine Foramen

Sphenopalatine foramen bridges the nasal cavity and the pterygopalatine fossa. This foramen is posterior to the middle turbinate.

The vital content of that foramen is:

  • Sphenopalatine artery of the maxillary artery
  • Nasopalatine segment of the maxillary nerve of the trigeminal nerve

How is the nasal cavity connected to the mouth? The nasal cavity is connected to the mouth by nasopharynx, which sits above the soft palate at the back of your nose.

What is the function of the nasal cavity?

Breathing, the sense of smell, and how both affect immunity are the key functions of the nasal cavity.

Olfaction refers to a sense of smell, where external chemical information is translated by the central nervous system. Our sense of smell is a complex process that is dependent on sensory organs, nerves, as well as the brain.

It is important for inhaled air to be warmed before it gets to the lungs. Air leaving the body via the nose returns moisture to the nasal cavity before being exhaled into the environment. This process happens in the respiratory area of the nasal cavity.

Cilia, which make up the tissue lining in the nasal cavity, join with mucus to filter the air that we breathe. Mucus traps small particles in the nasal cavity and the cilia functions to remove the mucus from the passageways.

Common Diseases of the Nasal Cavity

We outline the most common nasal and sinus disorders below:

  • Allergic rhinitis (upper airway disorder that affects individuals of all ages)
  • Triad asthma (a complex chronic medical condition involving a combination of 3 factors: asthma, aspirin allergy, and nasal polyps)
  • Chronic sinusitis with polyps (inflammation of the sinuses, persisting for 12+ weeks)
  • Chronic sinusitis without polyps
  • Deviated septums
  • Nasal fractures and nasal tumors

How the Nasal Cavity Impacts Sleep Apnea

Nasal obstruction in people with obstructive sleep apnea is common and has an effect on sleep quality.

Obstructive sleep apnea is a common sleep disorder. The most common side effects of sleep apnea include heart disease, respiratory dysfunction, type 2 diabetes, behavioral disorders, and impaired quality of life.

Sinusitis results when your sinus cavities struggle to drain properly. This struggle could indicate an underlying anatomy problem. This same problem could be causing your airway to become partially or completely blocked during sleep, triggering sleep apnea.

When you are asleep, your natural reflex is to breathe in and out through your nose for deeper breaths. Nevertheless, the sinus inflammation will force you not to breathe through the nose, but your mouth, which can result in detrimental health issues.

Because sinusitis symptoms make it more difficult to inhale during sleeping, someone with chronic sinusitis who does not get effective treatment is more likely to suffer from sleep apnea. When the sinusitis is treated properly, chronic sinusitis-associated sleep apnea may simply go away.

Sleep apnea is a chronic sleep condition, but sinusitis is a temporary infection. Hence, once you have treated the sinusitis, you will not have difficulty with breathing issues at night. So, if you think you have sleep apnea or chronic sinusitis, consult a doctor.

Sleep Apnea Treatment in New York, NY

Untreated sleep apnea is a serious threat to your wellness. If you have sleep apnea symptoms, you will need to speak to a biological dentist.

At Rejuvenation Dentistry, our dentists will evaluate your overall health, sleep apnea history, and introduce you to your treatment options like DNA appliance.

We can help diagnose sleep apnea and help you get the sleep you have been dreaming of.

Reduce your risk of getting health complications, so make an appointment now to see us at our Manhattan, NY office to get diagnosed.

Dr. Gerry Curatola is a renowned biologic restorative dentist with more than 40 years of clinical practice experience.

He studied neuroscience at Colgate University and attended dental school at the New York University (NYU) College of Dentistry where he now serves as Adjunct Clinical Associate Professor in the Department of Cariology and Comprehensive Care.