What are paranasal sinuses?

April 27, 2022

  

Have you ever had a toothache that feels like sinus pain? Or how about sinus pain that triggers a toothache? This happens because of the distinct relationship between teeth and the paranasal sinuses. These sinuses are centered on the nasal cavity and are the air-filled spaces located within the facial and cranial bones. Here is some basic anatomy of the paranasal sinuses, the functions of the sinuses, and why sinuses can trigger tooth pain.

What are the sets of paranasal sinuses?

There are four sets of paranasal sinuses. Each corresponds to the respective bone from which the name derives.

1. Frontal sinuses

The frontal sinuses are the most superior, or furthest up on the head. They are triangle-shaped cavities that sit above the orbits of the eyes located within the frontal bone. The cavities fan out from the bridge of the nose to the lower forehead. The frontal sinuses produce mucus which drains into the nose.

2. Ethmoid sinuses

The ethmoid sinuses sit directly between the orbits and open into the frontal nasal duct. These sinuses contain a series of 3 to 18 labyrinths. And based on the location of the apertures, the air cells of the ethmoid sinuses are divided into anterior, middle, and posterior regions.

3. Maxillary sinuses

These are the largest of the paranasal sinuses located bilaterally in the maxilla, with the pyramid shape almost filling the bone in its entirety. These sinuses help improve the respiratory function of the noise and are decisively involved in the production of nitrogen monoxide to help support the immune defense of the nasal cavity.

4. Sphenoid sinuses

Sphenoid sinuses sit within the sphenoid bone and are the most posterior paranasal sinuses.  The sphenoid sinuses are small at birth and continue to develop into puberty. And the size of the sphenoid septum varies from person to person. And the lateral wall of the sphenoid sinuses contains the medial wall of the optic canal.

What are the functions of the sinuses?

Sinuses fulfill various functions. First, they help warm and humidify inhaled air for easier breathing. As you breathe in through the nose, air flows through the nasal passages and sinuses. These passages are lined with cells that produce mucus so the nose and sinuses do not dry out during breathing. The mucus is also a way to support the immune defense of the nasal cavity by filtering the air. Second, sinuses help make the weight of the skull and head lighter and more manageable. The sinuses also increase the clarity and resonance of speech. And finally, paranasal sinuses serve as a crumple zone which helps protect vital structures in the event of facial trauma.

What do paranasal sinuses have to do with dentistry?

Of all the paranasal sinuses, the maxillary sinuses are the largest and the most important for dental clinicians. The maxillary sinuses are near the molars and premolars separated by only a thin sheet of bone. And the maxillary nerve supplies both the sinus and the teeth of the maxillary region. As such, inflammation in the sinus can present as a toothache and a toothache can present as inflammation of the sinus. Because the sinuses and teeth are so closely linked, it is important to pay attention to the issues and understand if it is time to call the physician or the dentist. 

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