FIG 1. CT scans of the temporal bones in an 87-year-old woman with a history of temporal bone surgery performed in the early 1940s.

A, Coronal-view scan obtained through the vestibule shows bony dehiscence of the lateral semicircular canal (open arrow) and a linear soft-tissue density closely applied to this defect. This is because of the fenestration surgery with creation of a labyrinthine window in the lateral semicircular canal and apposition of a tympanocutaneous flap (closed arrow).

B, Axial view.

C, Coronal-view scan obtained through the contralateral side shows the normal appearance of the lateral semicircular canals.

D, Axial view.