FIG 1. A and B, Normal anatomy of oval window on coronal (A) and axial (B) CT scans. V indicates vestibule; C, cochlea; S, lateral semicircular canal; single black arrows, margin of the oval window; asterisk, obturator foramen between stapes crura, well delineated on the axial scan; in A, arrowhead indicates horizontal facial nerve canal; cross, incudal body; single white arrow, incudal-stapedial articulation between the lenticular process and capitulum; in B, double black arrow indicates sinus tympani; double white arrow, neck of malleus. Posterior to the malleus lies the long process of the incus cut in cross section. Note that the facial nerve (arrowhead, A) is lateral to an imaginary vertical line drawn through the junction of the lateral and superior semicircular canals