title: Imaging of the superior rectus in superior rectus overaction after retrobulbar anesthesia.
abstract: OBJECTIVE
  Vertical diplopia after cataract surgery caused by an overaction of an extraocular muscle is more common when the superior rectus muscle is involved, whereas contracture is more common when the inferior rectus muscle is involved. However, no documented imaging has been presented. The aim of this report was to study the superior rectus in such a patient with magnetic resonance imaging (MRI).
  
  
  METHODS
  Observational case report.
  
  
  METHODS
  Ophthalmologic examination and thin-sectioned MRI across the superior rectus muscle were performed in a patient with superior rectus overaction after cataract surgery.
  
  
  METHODS
  Ocular alignment, ocular movement, and the superior rectus muscle on MRI.
  
  
  RESULTS
  Magnetic resonance imaging disclosed focal thickening of the superior rectus muscle near the orbital apex in a patient who showed superior rectus overaction after retrobulbar anesthesia for cataract extraction.
  
  
  CONCLUSIONS
  The focal thickening of the superior rectus muscle in this patient is consistent with the theory that segmental contracture leads to overactive muscles after retrobulbar anesthesia.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jae Hyoung
authors.initials: JH
authors.lastname: Kim
authors.forename: Jeong-Min
authors.initials: JM
authors.lastname: Hwang
mesh_terms: D000772:Anesthesia, Local / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000008:administration & dosage; D003286:Contracture / Q000139:chemically induced / Q000175:diagnosis*; D006801:Humans; D007267:Injections; D019654:Lens Implantation, Intraocular; D008012:Lidocaine / Q000008:administration & dosage; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000139:chemically induced / Q000175:diagnosis*; D009801:Oculomotor Muscles / Q000187:drug effects / Q000473:pathology*; D009915:Orbit; D018918:Phacoemulsification
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine