Which statement best differentiates neurapraxia from axonotmesis?

• A. Neurapraxia preserves axon continuity; axonotmesis disrupts the axon
• B. Axonotmesis preserves the myelin sheath
• C. Neurapraxia involves endoneurial disruption
• D. Neurotmesis preserves epineurium

Answer: (A)

Neurapraxia and axonotmesis differ mainly in whether the axon itself stays intact. In neurapraxia the axon remains continuous; the problem is demyelination enough to block conduction, so the nerve stays structurally intact and recovery is usually quick as remyelination occurs. In axonotmesis the axon is disrupted, with distal Wallerian degeneration, even though the surrounding connective tissue like the endoneurium may remain as a guide for regrowth. This disruption of the axon means a slower, potential for complete recovery depends on proper axonal regeneration along the preserved scaffolding.

Thus, the best differentiating statement is that neurapraxia preserves axon continuity while axonotmesis disrupts the axon. The other options don’t fit because axonotmesis does not preserve the myelin sheath, neurapraxia does not involve endoneurial disruption, and neurotmesis involves disruption rather than preservation of the epineurium.