Seddon classification of nerve injuries

Sir Herbert Seddon in 1942 described a scheme for describing nerve injuries according to the extent of damage to axons and surrounding connective tissue layers. It has clinical relevance in that it indicates the likely prognosis:

• neuropraxia:
  • no anatomical disruption
  • a localised, physiological and transient conduction block along a nerve
  • usually a result of a blunt injury
  • no distal Wallerian degeneration occurs
  • very variable, but often a motor paralysis with some residual sensory or autonomic function
  • nerve conduction studies show a conduction block at the level of the injury
  • typically, there is recovery in days to weeks
  • a diagnosis of exclusion
• axonotmesis:
  • axonal damage within the nerve
  • axonal degernation but endoneurial tubes and surrounding connective tissue elements remain intact
  • distal Wallerian degeneration
  • often the result of a more intensive blunt injury
  • full recovery is usual but may take weeks to months; there may be a residual deficit
• neurotmesis:
  • nerve divided
  • usually violent, open injuries
  • all axons and connective tissue elements disrupted
  • Wallerian degeneration distally
  • some recovery possible but much more likely with surgical nerve repair
  • full recovery unlikely