There are four paired sinus cavities that arise and pneumatize at different times during development. They are the maxillary, sphenoid, frontal, and ethmoid sinuses. The ethmoid sinuses are further divided into anterior and posterior sinuses by the basal lamella of the middle turbinate. The nasal cavity can be viewed as a box that is open at either end—the pyriform aperture and the choana–with a roof, a floor, and two side walls. The center piece of the “box” is the ethmoid complex, with which all other sinuses border and are intimately related.Concha Bullosa is considered as a common nasal anatomical variation and not referred as a disease. The middle concha is frequently affected by CB, in contrast; the superior and inferior conchae are rarely affected. The pneumatized middle concha is categorized into three groups based on the location of pneumatization site and extension.Several authors have assessed the relationship between sinonasal anatomic variants and the incidence of sinusitis. The incidence of Haller cells has been reported to vary from 2–45%, and although some reports have found a statistically significant relationship between maxillary sinusitis and medium or large Haller cells, it is generally believed that the presence of a Haller cell is not related to sinusitis. The incidence of agger nasi cells has been reported to vary from 3% to almost 100%, and its presence has been firmly associated with frontal sinusitis. The incidence of Onodi cells varies from 3.4–51%. Although not associated with sinusitis, its presence does pose an increased incidence of surgical complications. There are two anatomic variants, the middle turbinate concha bullosa and nasal septal deviation; however, adequate documentation of their anatomy and etiology has not appeared in the literature either to support or refute their roles in sinusitis. The incidence of CT findings positive for concha bullosa has varied from 14–53%, and the relationship of concha bullosa to paranasal sinus disease continues to be debated.

Sinonasal Anatomic Variants, sinusitis