Wiktionary
n. (paranasal sinus English)
Wikipedia
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoidal sinuses are behind the eyes. The sinuses are named for the facial bones in which they are located.
Usage examples of "paranasal sinuses".
His eyes were hurting now, seeming to expand beyond their sockets, and the way in which his paranasal sinuses were also expanding only made it worse, as though his face would detach from the rest of his skull.
He himself had subsequently diagnosed it as malignant and arranged for its removal, but the surgeon-friend who excised it had discovered preliminary invasions of both orbits as well as of the paranasal sinuses.