Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity (maxillary sinuses), above the eyes (frontal sinuses), between the eyes (ethmoid sinuses), and behind the ethmoids (sphenoid sinuses). The sinuses are named for the facial bones in which they are located.
Read more about Paranasal Sinuses: Types in Humans, Development, Sinuses in Animals, Biological Function, Ailments, Etymology, Additional Images