Which structure is a paranasal sinus located within the maxillary bone?

• A. Maxillary sinus
• B. Frontal sinus
• C. Ethmoid sinus
• D. Sphenoid sinus

Answer: (A)

Paranasal sinuses are air-filled cavities inside the skull that drain into the nasal cavity. The sinus housed within the maxillary bone is the maxillary sinus, which occupies the body of the maxilla and lies just lateral to the nasal cavity. It is the largest of the paranasal sinuses and drains into the middle nasal meatus via the maxillary ostium. The other paranasal sinuses reside in the frontal, ethmoid, and sphenoid bones.