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Precentral gyri hyperintensity, including the hand knob area (axial FLAIR)

Axial FLAIR sequence 3 weeks after symptom onset in osmotic demyelination syndrome showing hyperintensity in the precentral gyri bilaterally, including the hand knob area ("hand knob sign"). (Source: Siranart N, Nakaphan P, Viarasilpa V, Anukoolwittaya P, Hemachudha P. Hand knob sign in osmotic demyelinating syndrome. BMC Neurol 2024;24[1]:83. Creative Commons Attribution 4.0 International [CC BY 4.0] license,

Associated Disorders

  • Alcoholism
  • Extrapontine myelinolysis
  • Hyperosmolar hyperglycemic state
  • Hypokalemia
  • Malnutrition
  • Osmotic myelinolysis