Peripheral nerve Injuries

Question 1

Common mechanism of axillary nerve injury

Answer 1

Fracture of neck of humerus

Anterior gh dislocation

Question 2

Common mechanism of musculocutaneous nerve injury

Answer 2

Clavicle fx

Question 3

Wallerian degeneration

Answer 3

Degeneration of myelin sheath and axon occurs distal to injury.

Question 4

Neurapraxia

Answer 4

Mildest form of nerve injury

Conduction block due to myelin dysfunction. Axon is still intact. Rapid recovery

Question 5

Axonotmesis

Answer 5

Reversible damage to axon with preservation of endoneurium and other supporting structures
Distal Wallerian degeneration can occur
Regeneration dismally: 1 mm/ day

Question 6

Neurotmesis

Answer 6

Irreversible damage to axon, myelin, and connective tissue components.
No spontaneous recovery. May see regeneration with surgical re attachment