What are the paranasl sinuses?

Paranasal sinuses are air-filled spaces located within the bones of the skull, specifically around the nasal cavity. They include four main pairs: the frontal, maxillary, ethmoid, and sphenoid sinuses. These sinuses help to lighten the skull, enhance voice resonance, and produce mucus that moisten the nasal passages. Additionally, they play a role in immune defense by trapping pathogens and particles.