- Discussion:
- arises from severe nerve injury (
axonotmesis or
neurotmesis)
- characterized by axonal enlargement into an amorphorous mass, breakdown of the axons, and schwann cell
ingestion of fragmented myelin to provide clean endoneural tubes for advancement of regenerating axons;
- axonal sprouting begins within 96 hours;
- if axonal regeneration is delayed, tubes undergo shrinkage that becomes more severe with time;
- Pathologic Findings:
- cell body:
- increases in size;
- migration of nucleus to the cell periphery;
- proximal nerve segment:
- degeneration occurs proportionate to severity of injury;
- degeneration extends proximally to the next node of Ranvier;
- distal nerve segment:
- Schwann cell proliferation;
- collapse of endoneurial tubes;
- distally the entire axonal material is phagocytosed from the site of injury to the endplates;
