fig 3.

Case 3.

A, Axial HRCT section passing through the attici shows a sulcus (arrows) about 2 mm thick, originating from the anterior portion of the transverse sinus and passing anteriorly through the lateral portion of the petrous bone. Also shown are middle ear hypoplasia and posterior semicircular canal aplasia.

B, Axial CT section 5 mm below A shows the PSS entering into a retroarticulare foramen. Note the dehiscence of the genu of the facial nerve (white arrowhead).

C, HRCT 10 mm below B shows aplasia of the jugular foramen. Posterior condylar and mastoid canals (arrow) are illustrated.