title: Congenital monocular elevation deficiency.
abstract: OBJECTIVE
  The pathophysiology of monocular elevation deficiency is poorly understood. The goal of this study was to determine the appearance of the extraocular muscles and the oculomotor nerve.
  
  
  METHODS
  Observational case series.
  
  
  METHODS
  Six patients with monocular elevation deficiency.
  
  
  METHODS
  Ophthalmologic examination and thin-sectioned magnetic resonance imaging (MRI) at the brainstem level as well as across the orbit in 6 patients were performed.
  
  
  METHODS
  Ocular alignment and movement, extraocular muscles, and the oculomotor nerve on MRI.
  
  
  RESULTS
  One out of 6 patients with monocular elevation deficiency showed focal thickening of the inferior rectus muscle near the orbital apex. The 5 remaining patients showed normal extraocular muscles and the oculomotor nerves on MRI.
  
  
  CONCLUSIONS
  Focal thickening of the inferior rectus muscle may partially explain the cause of restricted gaze. In addition, the finding of normal oculomotor nerves might support an underlying deficit in the unilateral center for upgaze as the etiology of monocular elevation deficiency.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Bundang-gu, Seongnam, Gyeonggi-do, Korea.
authors.forename: Jae Hyoung
authors.initials: JH
authors.lastname: Kim
authors.forename: Jeong-Min
authors.initials: JM
authors.lastname: Hwang
mesh_terms: D000328:Adult; D002675:Child, Preschool; D005133:Eye Movements; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009801:Oculomotor Muscles / Q000294:innervation / Q000503:physiopathology*; D009802:Oculomotor Nerve / Q000503:physiopathology*; D009886:Ophthalmoplegia / Q000151:congenital* / Q000503:physiopathology*