Paranasal sinuses are air-filled spaces, communicating with the nasal cavity, within the bones of the skull and face. Types in humans Humans possess a number of paranasal sinuses, divided into subgroups that are named according to the bones within which the sinuses lie: the maxillary sinuses, also called the maxillary antra and the largest of the paranasal sinuses, are under the eyes, in the maxillary bones (cheek bones). the frontal sinuses, over the eyes, in the frontal bone, which forms the… (More on Sinuses)