A. Coronal slice through the ethmoid and maxillary sinuses:  right inferior turbinate (1); right middle turbinate (2); left middle meatus, providing drainage and aeration of the left maxillary sinus (3).

B. Axial slice through the frontal sinus: anterior wall (1); posterior wall (2).

C. Axial slice through the maxillary sinuses: right maxillary sinus (1)  right medial wall (2); nasal septum (3).

D. Axial slice through the ethmoid sinuses: left ethmoid sinus (1); right sphenoidal sinus (2).