Definition
Air-filled cavities located within the cheekbones on either side of the nose, connected to the nasal passages by small openings. As one of the paranasal sinuses, they must equalize pressure with the surrounding atmosphere during climbs and descents; if the connecting opening is blocked by congestion, trapped air cannot expand or contract freely, causing pain and possible incapacitation in flight.
Plain English
Hollow spaces inside your cheekbones that are connected to your nose by tiny passages. They normally let air flow in and out so the pressure inside matches the air around you. When you have a cold and the passages get blocked, the air can get trapped and cause sharp pain when you climb or descend.
Context Anchor
Seen in aeromedical discussions about sinus pain, head colds, allergies, and flying during climbs or descents.
Derivation
From Latin maxilla meaning 'jawbone' or 'upper jaw.' These sinuses sit in the bone of the upper jaw, just below the eyes and beside the nose — hence the name.
Why Pilots Care
Blocked maxillary sinuses can produce sharp facial pain during climb or descent because trapped air cannot equalize with changing outside pressure.
Grounding Statement
Picture a small air space behind each cheek that must keep matching the outside air pressure as the airplane changes altitude.
Intuition Check
Maxillary does not mean maximum or extra large here. It means related to the upper jaw and cheek area.
Example Sentence 1
The pilot cancelled the flight because congestion in his maxillary sinuses meant a descent could trigger a painful sinus block.
Example Sentence 2
Before takeoff the pilot made sure the maxillary sinuses were clear to prevent discomfort at altitude.