The sinuses are air-filled spaces located within the bones of the face and skull. They are connected to the nasal cavity and help to lighten the weight of the skull, improve voice resonance, and produce mucus that keeps the nasal passages moist. There are four main pairs of sinuses: the frontal, maxillary, ethmoid, and sphenoid sinuses. When the sinuses become inflamed or infected, a condition known as sinusitis can occur. This can lead to symptoms such as nasal congestion, facial pain, and headaches. Maintaining good nasal hygiene and staying hydrated can help support sinus health and prevent infections.