Standard classifications of nerve injury mechanisms [15]
| Sunderland | Seddon | Features |
|---|---|---|
| 1st degree | Neurapraxia | Segmental demyelination (damage is limited to myelin sheath alone) |
| 2nd degree | Axonotmesis | Despite the axon being severed, the endoneurium is protected |
| 3rd degree | Axonotmesis | There is axon and endoneurium discontinuity, but there is no impact on perineurium |
| 4th degree | Axonotmesis | Discontinuity of axons, the endoneurium, and perineurium |
| 5th degree | Neurotmesis | Absence of continuity throughout the nerve, encompassing the epineurium |
Note. Adapted from “Peripheral nerve injury: A review article” by Seddighi A, Nikouei A, Seddighi AS, Zali AR, Tabatabaei SM, Sheykhi AR, et al. Int Clin Neurosci J. 2016;3:1–6 (https://journals.sbmu.ac.ir/Neuroscience/article/view/12016). CC BY.