The maxillary sinuses are air-filled spaces located within the maxilla, or upper jawbone, on either side of the nose. They are the largest of the paranasal sinuses and play a role in reducing the weight of the skull, enhancing voice resonance, and producing mucus to keep the nasal passages moist. These sinuses are lined with a mucous membrane that can become inflamed due to infections or allergies, leading to a condition known as sinusitis. Symptoms of sinusitis may include facial pain, nasal congestion, and headaches, highlighting the importance of the maxillary sinuses in overall respiratory health.