ABSTRACT
The radiologist must be familiar with the anatomy of the ethmoid labyrinth, the larger paranasal sinuses, and their associated ventilation and drainage channels in the lateral nasal wall. Each radiologist will need to develop their own scheme for the systematic reporting of computed tomography scans of this challenging anatomical area. The external nose and the nasal bones are the first structures to be visualized in coronal scans. If the frontal sinuses are prominent, they will also appear in the most anterior scans. Most septal deviations are the result of developmental anomalies and asymmetric growth of the facial skeleton, although the nasal septum may be deviated from trauma. Isolated frontal recess disease with secondary infection of a crista galli air cell may have normal endoscopy. The frontal sinus is connected to the nasal cavity by the frontal recess. The route of ventilation and drainage of the frontal sinus through the frontal recess depends upon embryological development.
