25 Days of Skeletal Facts: Day 21 – The Sinuses

Happy Monday and Happy Winter Solstice! Let’s talk sinuses. The paranasal sinuses consist of pneumatized, or air filled, spaces within four different bones of your skull. Each is named for the bone in which they reside. You are most likely familiar with your maxillary sinus, the largest and most commonly infected sinus, which sits under the eyes on either side of the nose within your maxilla. In the image below, you can also see your frontal, ethmoidal, and sphenoidal sinuses. Each paranasal sinus has a mucosal lining and fluid build up from each drains into your nose.

Paranasal sinuses. Source: National Cancer Institute

The actual function of the paranasal sinuses is somewhat of an anatomical and physiological mystery. They may support the immune function of the nasal cavity or were built in to make your skull lighter. Awareness of the paranasal sinuses may date back to the ancient Egyptians, who detailed the anatomy of the maxilla in their writings and in the process of mummification, removed the brain through the nasal cavity, possibly via the ethmoidal sinus – making them the premier sinus surgeons (Mavrodi & Paraskevas 2013). And while not officially discovered until years after, a drawing by Leonardo da Vinci, seen below, clearly depicts both the frontal and maxillary sinus (Jose 2001). It is Nathaniel Hawthorne (1613-1685), a British anatomist, who is credited with the first descriptions of the front, maxillary, and ethmoidal sinuses (Mavrodi & Paraskevas 2013).

Anatomical drawing by Leonardo da Vinci, featuring frontal and maxillary sinuses. Source: Mavrodi & Paraskevas 2013

That’s a wrap on the mysterious paranasal sinuses. Tomorrow we explore the sutures of your skull.


The Paranasal Sinuses. TeachMe Anatomy Series. 2020

Evolution of the paranasal sinuses’ anatomy through the ages. Mavrodi & Paraskevas. NCBI. 2013

Anatomy and Leonardo da Vinci. Jose. YJBM. 2001

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