Peripheral nerve injury classification depends on which anatomical layers are damaged, determining whether a nerve heals itself or requires surgical repair. Master the Seddon and Sunderland classifications alongside the biology of Wallerian degeneration and the crucial one millimetre per day axonal regeneration rule. ⏱ Chapters 0:00 Intro 0:13 BASIC SCIENCE · NERVE INJURY 0:32 The Anatomy That Decides Everything 1:25 Seddon Counts Outcomes. Sunderland Counts La… 1:41 Sunderland'S Five Degrees 2:45 Wallerian Degeneration — Demolition And Rebu… 3:42 Regeneration — A Millimetre A Day 4:35 Tinel'S Sign — The Marching Regeneration Fro… 5:07 Two Clocks: Schwann Bands Fade After 3–4 Mon… 5:33 Recap & sources This video provides a comprehensive, fellowship-level guide to nerve injury and regeneration, explaining the complex anatomy of peripheral nerves and the biological processes that dictate clinical outcomes. Covering everything from the initial cellular responses like Wallerian degeneration and chromatolysis to the formation of Schwann cell bands of Büngner, viewers will understand exactly how to classify nerve damage, predict recovery times, and determine the optimal windows for surgical nerve repair. 🦴 IN THIS VIDEO YOU'LL LEARN • The precise anatomical layers of a peripheral nerve from the axon out to the epineurium • How to accurately classify nerve injuries using both the Seddon and Sunderland grading systems • The step-by-step cellular biology of Wallerian degeneration following peripheral nerve transection • How chromatolysis reprogrammes the neuronal cell body from transmission mode to growth mode • The critical role of Schwann cells in clearing inhibitory debris and forming the bands of Büngner • Why the axonal growth cone advances at a rate of approximately one millimetre per day • How to clinically differentiate between neurapraxia, axonotmesis and neurotmesis • The importance of endoneurial tube preservation for guiding successful nerve regeneration • How to calculate expected recovery times and understand the optimal surgical windows for repair 📌 KEY TAKEAWAYS ✔️ First and second degree Sunderland injuries retain their endoneurial scaffold and heal spontaneously; third degree and deeper injuries fail without surgical intervention. ✔️ Wallerian degeneration is an active, organised demolition process beginning within 24 to 48 hours, essential for clearing inhibitory myelin debris. ✔️ Schwann cells completely change character to phagocytose debris and line up inside surviving endoneurial tubes to form the bands of Büngner. ✔️ Neuronal cell bodies undergo chromatolysis, moving the nucleus to the edge and peaking protein factory retooling at 7 to 14 days. ✔️ Regenerating axons rely on intact anatomical guide-rails; without them, they wander and form painful neuromas. ✔️ At a regeneration rate of one millimetre a day, proximal nerve injuries frequently exceed the 18 to 24 month window of motor endplate viability. 👩⚕️ WHO THIS IS FOR This video is designed for orthopaedic trainees, medical students, clinicians, and curious patients who want a deep, medically accurate understanding of peripheral nerve biology and the principles dictating surgical decision-making. 📚 RELATED TOPICS: Brachial plexus injury assessment and classification · Electrodiagnostic testing and EMG interpretation for nerve injuries · Surgical techniques for primary and secondary nerve repair · Carpal tunnel syndrome and compressive neuropathies · Management of painful neuromas · Peripheral nerve tumours and sheath lesions 🔗 More free orthopaedic teaching at Orthovellum.com — subscribe for weekly videos. 🎨 CREDITS • Original Orthovellum production. ⚠️ DISCLAIMER: Educational only — not individual medical advice. Always consult a qualified clinician for diagnosis and treatment. #orthopaedics #nerveinjury #neuroregeneration #sunderlandclassification #seddonclassification #walleriandegeneration #peripheralnerve #neurosurgery #handsurgery #orthopaedicsurgery #medicalbiology #anatomy #physiology #neuroapraxia #axonotmesis