Dehiscence or Thinning of Bone Overlying the Superior Semicircular Canal in a Temporal Bone Survey

Abstract

Dehiscence of bone overlying the superior canal occurred in approximately 0.5% of temporal bone specimens (0.7% of individuals). In an additional 1.4% of specimens (1.3% of individuals), the bone was markedly thin (< or =0.1 mm), such that it might appear dehiscent even on ultra-high-resolution computed tomography of the temporal bone. Sites affected were in the middle fossa floor or a deep groove for the superior petrosal sinus, often bilaterally. These abnormalities may arise from failure of postnatal bone development. Thin areas of bone over the superior canal may be predisposed to disruption by trauma.