Coronal imaging of the osteomeatal unit: anatomy of 24 variants.

The purpose of this paper is to present a user-friendly reference for 24 of the most common normal variants of the osteomeatal unit. A five image set of consecutive normal coronal hanging head computed tomography (CT) images was obtained. Half of each image was duplicated enough times to allow superimposition of the variants. For organizational purposes, each variant was sorted into six color-coded regions: middle turbinate (five variants), inferior turbinate (three variants), maxillary sinus (three variants), nasal septum (three variants), ethmoid sinuses (five variants), and uncinate process (five variants). This reference can be used to rapidly identify a CT scan level and obtain an overview of common variants in that level. In addition, the color-coded system can be used to find any variant on all appropriate CT levels quickly by locating its colored column.