Which sinus is located directly behind the forehead?

The frontal sinus is located directly behind the forehead, making it the correct answer to the question. This sinus is part of the paranasal sinuses and is situated above the orbits, and its anatomical position allows it to contribute to the overall structure of the forehead region.

The frontal sinus plays a role in the resonance of the voice and acts as a protective buffer against facial trauma. It also helps reduce the weight of the skull and provides an area for the production of mucus that helps moisturize the nasal cavity.

The other sinuses mentioned have distinct locations: the maxillary sinus is found in the cheek area, the sphenoid sinus is positioned deeper in the skull behind the nasal cavity, and the ethmoid sinus is located between the nose and the eyes. Understanding these anatomical positions is vital for comprehending sinus-related conditions and their implications in medical practice.