Neurotmesis corresponds to which type of nerve injury?

Neurotmesis corresponds to which type of nerve injury?

• A. Type I nerve injury
• B. Type II nerve injury
• C. Type III nerve injury
• D. Complete transection with preserved endoneurium

Answer: (C)

Neurotmesis is the most severe nerve injury, involving complete disruption of the nerve and all its connective tissue coverings. In the grading system used here, this level of disruption corresponds to the most advanced category, where the axon is severed and the endoneurial, perineurial, and epineurial structures are all lost. Because the nerve’s internal architecture is destroyed, spontaneous reinnervation is unlikely and surgical repair is usually required. To contrast, milder injuries have intact connective tissue scaffolding: neurapraxia blocks conduction without axonal disruption, and axonotmesis damages the axon with preservation of the endoneurium (and other coverings to varying extents), allowing some guided regrowth. The complete transection with preserved endoneurium described in some options does not fit neurotmesis, which entails disruption of those coverings.

Neurotmesis is the most severe nerve injury, involving complete disruption of the nerve and all its connective tissue coverings. In the grading system used here, this level of disruption corresponds to the most advanced category, where the axon is severed and the endoneurial, perineurial, and epineurial structures are all lost. Because the nerve’s internal architecture is destroyed, spontaneous reinnervation is unlikely and surgical repair is usually required.

To contrast, milder injuries have intact connective tissue scaffolding: neurapraxia blocks conduction without axonal disruption, and axonotmesis damages the axon with preservation of the endoneurium (and other coverings to varying extents), allowing some guided regrowth. The complete transection with preserved endoneurium described in some options does not fit neurotmesis, which entails disruption of those coverings.