The three cranial bones that contain paranasal sinuses are the maxillary bones, the frontal bone and the sphenoid bone. The ethmoid bone also contains a group of air-filled cavities that are often also considered paranasal sinuses.
Sinuses are air-filled cavities within facial bones and are named for the bones that surround them. The frontal bone rests above the eyes between the eyebrows and contains the frontal sinus. Between the eyes and beneath the frontal bone is the ethmoid bone, which contains the group of small ethmoidal sinuses. Behind the ethmoid bone is the sphenoid bone, which contains the sphenoid sinus. Under the eyes on either side of the nose are the maxillary bones, which contain the maxillary sinuses.