ABSTRACT
This chapter discusses important anatomical variants in the sinuses and the nasal cavity of which surgeons must be aware prior to any intervention. Direct endoscopic examination and visualization of the small clefts of the ostiomeatal complex are not possible, and consequently computed tomography (CT), especially in the coronal plane, is essential for the assessment of the patient with recurrent or persistent sinusitis. Coronal CT allows the radiologist to determine the site and extent of disease in the paranasal sinuses and in the surrounding soft tissues and to identify those anatomical variants that may predispose the individual to sinusitis. Enlarged agger nasi cells may involve the frontal recess either by obstructing the frontal recess mechanically if they are well developed or by direct spread of inflammation. The commonest anatomical variants associated with inflammatory disease of the adjacent paranasal sinuses are medial deviations and elongated free margins of the uncinate process.
