Maxillary sinus
Sinus maxillaris
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- What it is
- The largest paranasal sinus: a pyramid-shaped air space in the body of the maxilla, below the orbit and above the upper molar roots, with its base on the lateral nasal wall.
- Function
- Lightens the face and warms/humidifies air; it drains into the middle meatus.
- Size
- About 3.5 cm high, 2.5 cm wide and 3.5 cm deep (~15 ml).
- Clinical note
- Its opening lies high on the medial wall, so it drains poorly and is the sinus most often infected; upper molar roots can protrude into its floor.