Sunderland classification

Sunderland's 1951 five-degree classification of nerve injury by the connective-tissue layer lost: first degree (neurapraxia), second (axon only, endoneurium intact — full recovery), third (endoneurium disrupted — partial recovery), fourth (perineurium disrupted — usually needs surgery) and fifth (complete transection). Mackinnon and Dellon added a sixth degree for mixed injuries.

Related terms

• Glossary

  Seddon classification

  Seddon's three-grade classification of peripheral nerve injury, published in 1942–1943: neurapraxia (segmental demyelination with an intact axon), axonotmesis (axonal interruption with a preserved connective-tissue framework) and neurotmesis (complete transection). It remains the classification used in most clinical descriptions.

• Anatomy

  Endoneurium

  The innermost connective-tissue layer of a peripheral nerve, enclosing each axon and its Schwann cells within the fascicle bounded by the perineurium. The endoneurial tube guides regenerating axons back to their original targets; its preservation distinguishes a second-degree (fully recovering) injury from a third-degree one.

• Condition

  Neuroma-in-continuity

  A scarred, thickened segment of an injured nerve that remains in anatomical continuity, in which regenerating axons are trapped in fibrous tissue and a variable number cross to the distal stump. Whether to neurolyse it or to resect and graft it is decided by time, examination and intraoperative nerve action potential recording, because no pre-operative test grades it reliably.

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.

← Back to glossary