title: Treatment and diagnosis of congenital fourth nerve palsies: an update.
abstract: OBJECTIVE
  This review discusses recent advances in our understanding of the pathology, diagnosis, and treatment of congenital fourth nerve palsies.
  
  
  RESULTS
  High-definition MRI, which can now more accurately image the trochlear nerve, has increased our understanding of the pathology of fourth nerve palsies. A more sensitive two-step test is proposed to replace the three-step Parks-Bielschowsky test. Procedures strengthening the superior oblique tendon can be performed with a low incidence of secondary Brown syndrome.
  
  
  CONCLUSIONS
  Recent MRI studies have shown two pathological mechanisms associated with congenital superior oblique palsies. Superior oblique tuck combined with inferior oblique recession is a very effective way of eliminating head tilt secondary to congenital fourth nerve palsies.
authors.affiliation: Division of Pediatric Ophthalmology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey and Wills Eye Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: J Mark
authors.initials: JM
authors.lastname: Engel
mesh_terms: D000818:Animals; D006801:Humans; D008279:Magnetic Resonance Imaging; D015835:Ocular Motility Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D009801:Oculomotor Muscles / Q000473:pathology; D020432:Trochlear Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*