title: Rotation of the osseous spiral lamina from the hook region along the basal turn of the cochlea: results of a magnetic resonance image anatomical study using high-resolution DRIVE sequences.
abstract: OBJECTIVE
  To define the rotational anatomy of the osseous spiral lamina (OSL) at the hook region and along the basal turn of the cochlea and to illustrate the potential utility of high-resolution MRI images to study inner ear ultrastructure.
  
  
  METHODS
  Retrospective review of high-resolution temporal bone MRI images in 20 consecutive adult patients referred for imaging unrelated to hearing loss. The main outcome measure utilised images in an oblique sagittal plane to measure the rotation of the OSL relative to the vertical axis in the hook region and along the basal turn of the cochlea.
  
  
  RESULTS
  The right OSL is noted to rotate in a clockwise direction as one proceeds anteriorly; over the same distance, the left OSL rotates in an anti-clockwise direction. The average overall rotation for all subjects as measured over a distance of 1-7 mm from the posterior margin of the round window was 25.95°. Inter-subject variability was noted.
  
  
  CONCLUSIONS
  Prominent rotation of the OSL was noted in the hook region, this being most pronounced in the proximity to the round window. This concept may have implications for cochleostomy site selection with implant surgery. The study highlights the feasibility of high-resolution MRI to be used to systematically study variations in intra-cochlear anatomy.
authors: Radiology Department, Queen Alexandra Hospital, Southwick Hill Road, Cosham, Portsmouth, Hampshire, PO6 3LY, UK. daren.gibson@porthosp.nhs.uk
authors: Daren
authors: D
authors: Gibson
authors: Michael B
authors: MB
authors: Gluth
authors: Andy
authors: A
authors: Whyte
authors: Marcus D
authors: MD
authors: Atlas
mesh_terms: D000328:Adult; D000368:Aged; D003051:Cochlea / Q000033:anatomy & histology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013137:Spiral Lamina / Q000033:anatomy & histology*; D013701:Temporal Bone / Q000033:anatomy & histology; D055815:Young Adult