ABSTRACT
The paranasal sinuses are divided into two anatomical groups. The maxillary sinus, the frontal sinus and the anterior ethmoid cells form the anterior group. The posterior group includes the posterior ethmoid cells (PEC) and the sphenoid sinus. The posterior group is closely related to the orbital apex, optic nerve and the cavernous sinus. Although pathology in the posterior group is not as common as in the anterior group, disease in this cell complex may cause serious complications including impairment of vision, blindness, cranial nerve palsies and thrombophlebitis of the cavernous sinus.
