Which bones contain paranasal sinuses, and what are their functions?

• A. Temporal and occipital bones.
• B. Frontal, maxillary, sphenoid, and ethmoid bones contain paranasal sinuses; they lighten the skull, warm and humidify air, and resonate voice.
• C. Parietal bone only.
• D. Mandible and zygomatic bones.

Answer: (B)

Paranasal sinuses are air-filled cavities that open into the nasal cavity, located within four skull bones: the frontal, maxillary, sphenoid, and ethmoid bones. Their purpose is to lighten the head by reducing skull weight, and to condition inspired air by warming and humidifying it as it travels through the nasal passages. They also help shape and resonate the voice. Additionally, the mucous lining of these sinuses helps trap and remove particles, keeping the nasal passages moist and protected. Other bones listed do not contain paranasal sinuses—temporal and occipital bones, the parietal bone, and the mandible or zygomatic bones do not house these sinus cavities.