The Sunderland classification is used to categorize peripheral nerve lesions into five different degrees and was published in 1951[^1].
Classification
Grade | Description |
1 | Neurapraxia, or physiological conduction block, in which the nerve has lost its conduction function. There are no anatomical changes. |
2 | Axonotmesis with an intact endoneurium. |
3 | Axonotmesis with disruption of the endoneurium (axonal lesion with degeneration of the distal segments). The perineurium and basement membrane of the Schwann cells are intact. |
4 | Here, the perineurium is additionally disrupted. The internal nerve architecture is destroyed, and the fascicular structure has been lost or replaced by scar tissue. Continuity is maintained only by the interfascicular and epifascicular epineurium, which itself has become fibrotic as a result of the trauma. |
5 | Here, epineurial continuity is additionally disrupted (Neurotmesis with discontinuity of the nerve due to clean transection or rupture of the nerve). |