Surgery>>>>>Wound Healing
Question 9#

What type of nerve injury involves disruption of axonal continuity with preserved Schwann cell basal lamina? 

a. Neurapraxia
b. Axonotemesis
c. Neurotmesis
d. Axonolysis

Correct Answer is B

Comment:

There are three types of nerve injuries: neurapraxia (focal demyelination), axonotmesis (interruption of axonal continuity but preservation of Schwann cell basal lamina), and neurotmesis (complete transection). Following all types of injury, the nerve ends progress through a predictable pattern of changes involving three crucial steps:

  1. survival of axonal cell bodies;
  2. regeneration of axons that grow across the transected nerve to reach the distal stump; and
  3. migration and connection of the regenerating nerve ends to the appropriate nerve ends or organ targets.

Phagocytes remove the degenerating axons and myelin sheath from the distal stump (Wallerian degeneration). Regenerating axonal sprouts extend from the proximal stump and probe the distal stump and the surrounding tissues. Schwann cells ensheathe and help in remyelinating the regenerating axons. Functional units are formed when the regenerating axons connect with the appropriate end targets.