title: Dehiscence of the bony roof of the superior semicircular canal in the middle cranial fossa.
abstract: Spontaneous dehiscence of the superior semicircular canal (SSC) in the middle cranial fossa is rare and may cause clinical problems. This dehiscence was investigated in cadaveric and dried temporal bone specimens. One cadaveric specimen showed a spontaneous defect: the dehiscence was a symmetrical, elongated ellipse with smooth margins. Four of 244 dry bone specimens showed bony defects in the roof of the SSC, however, only one specimen was thought to have a spontaneous defect. Based on computer-simulation models, we hypothesized that spontaneous defects of the SSC may arise during the fetal period. Although rare, this defect may cause problems in middle cranial fossa surgery and may relate to certain vertiginous disorders.
authors.affiliation: Department of Anatomy and Developmental Biology, University College London, UK. atsunoda@mac.com
authors.forename: Atsunobu
authors.initials: A
authors.lastname: Tsunoda
authors.forename: Omi
authors.initials: O
authors.lastname: Terasaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D008953:Models, Anatomic; D012665:Semicircular Canals / Q000002:abnormalities* / Q000196:embryology / Q000648:ultrastructure; D013701:Temporal Bone / Q000002:abnormalities* / Q000196:embryology / Q000648:ultrastructure