Anatomic variants of paranasal sinuses

During the last 15 years period, the development of functional endoscopic sinus surgery underlines the needs of a better knowledge of sinonasal anatomy and consequently, of sinonasal anatomic variations. These anatomic variations are widely spread into the population and commonly encountered in daily CT practice. The difference of anatomic landmarks during endoscopic surgery can result in bony transgression and increase the difficulties of the surgery. In fact, functional endoscopic surgery is a <<blind>> surgery leading to severe complications with medico-legal impact. Therefore, the anatomic sinonasal variations should be depicted in all sinonasal CT imaging studies irrespective of the indications. Moreover, some anatomical variants may cause certain symptoms.