Figure 2. High-resolution temporal bone CT without IV contrast in the Pöschl projection. (A) Segmental dehiscence of the right superior semicircular canal (arrow) and segmental dehiscence of the adjacent portion of the right tegmen tympani (arrowhead). (B) Normal configuration of both the left SSC (arrow) and left tegmen tympani (arrowhead), both demonstrating adequate osseus coverage. Note that the anterior and posterior limbs of the superior semicircular canals appear to have normal caliber and are symmetric, measuring between 1.0 and 1.2 mm in diameter.