Which sinus is located in the frontal bone?

The frontal sinus is located within the frontal bone of the skull. This sinus is part of the paranasal sinus system, which includes various other sinuses that are associated with the nasal cavity. The frontal sinuses are specifically situated above the eyes and behind the forehead, contributing to functions such as lightening the weight of the skull, producing mucus to keep the nasal passages moist, and contributing to voice resonance.

In terms of the other options, the sphenoid sinus is located in the sphenoid bone, the maxillary sinus is found in the maxilla (upper jaw bone), and the ethmoid sinus is situated within the ethmoid bone between the eyes. Each of these sinuses has distinct anatomical locations and functions, but the frontal sinus is uniquely associated with the frontal bone, making it the correct answer.