Nerve injury classification

Nerve injury classification describes the various features of nerve injury on MRI with respect to pathological events.


  • neuropraxia
    • grade I: there is increased T2/STIR signal in the nerve, however the muscle appears normal
  • axonotmesis
    • grade II: increased T2/STIR signal in nerve and muscle (pathologically there is myelin and axonal injury but the endoneurium is intact) 
    • grade III: enlargement of nerve fascicles which corresponds pathologically to myelin and axonal injury with involvement of endoneurium but intact perineurium
    • grade IV: neuroma in continuity, disruption of nerve fascicles results in inability of regenerating nerve to reach distal targets, pathologically there is myelin and axonal injury with involvement of endoneurium and perineurium but epineurium is intact
  • neurotmesis
    • grade V: complete disruption of continuity of nerve with or without haemorrhage and fibrosis in the gap, the muscle shows hyperintensity but with time atrophies and undergoes fatty replacement
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Article information

rID: 47058
Synonyms or Alternate Spellings:
  • Classification of nerve injury
  • Seddon and Sunderland classification

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