Figure 1

High-resolution multi-detector CT of the temporal bone was performed with 0.625 mm slices and reformations of the SSC along the longitudinal axis (Pöschl view) and transverse axis (Stenvers view). To measure the extent of dehiscence, a straight line was drawn subtending the arc of the SSC and rounding to the nearest 0.5 mm in the Pöschl view [3]. In patient 1, the petrous bone overlying the right SSC was eroded, but without dehiscence, as seen on the (A) Pöschl view and (C) Stenvers view. However, there was dehiscence of the left SSC as seen on the (B) Pöschl view (arrowhead) and (D) Stenvers views (arrow).