Wallerian degeneration

The programmed breakdown of the axon and its myelin distal to a nerve injury that has interrupted the axon, beginning within 24–48 hours. Schwann cells shed myelin and proliferate, macrophages clear the debris, and the empty endoneurial tubes are lined by bands of Büngner along which regenerating axons later grow. It does not occur in neurapraxia.

Related terms

• Anatomy

  Bands of Büngner

  Longitudinal columns of proliferating Schwann cells that fill the empty endoneurial tubes of the distal nerve stump after Wallerian degeneration and guide regenerating axons back towards their targets. Their growth-supportive state is time-limited, which is one reason delayed repair does badly.

• Condition

  Axonotmesis

  Seddon's intermediate grade of nerve injury: the axons are interrupted and undergo Wallerian degeneration, but the connective-tissue framework of the nerve is preserved to a varying degree. Sunderland subdivides it into second, third and fourth degrees according to whether the endoneurium and perineurium survive; recovery ranges from complete (second degree) to poor without surgery (fourth degree).

Articles mentioning this term

1. FESSH preparation · 26 September 2026

   Peripheral nerve injury and repair

   Peripheral nerve injury for FESSH candidates: degeneration, Seddon and Sunderland grades, electrodiagnosis, timing, grafts, conduits and nerve transfers.

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