Classification of Acute Nerve Injuries: Neuropraxia, Axonotmesis, Neurotmesis

Question 1

Neuropraxia

Answer 1

Mildest form of injury

• Conduction block usually due to myelin dysfunction
• axonal continuity preserved
• Nerve fibers are NOT damaged, no evidence of nerve degeneration is noted

Recovery is generally rapid and complete can occur in 4 - 6 weeks

Question 2

Symptoms of Neuropraxia

Answer 2

Pain
Minimal Muscle Atrophy
Numbness or greater loss of motor and sensory functions
Diminished Proprioception

Question 3

Axonotmesis

Answer 3

More severe grade, girl lets say medium severity

• Injury is reversible as the anatomical relation is still maintained
• Damage to the axons with preservation to the endoneurium, epineurium, Schwann Cells and supporting cast and crew
• Distal Wallerian Degeneration can occur

Question 4

Axonotmesis nerve regeneration

Answer 4

Nerve can regenerate distal to the site of the lesion at a rate of one millimeter per day

• Recovery is spontaneous and varies
• May need surgery for repair

Question 5

Most common causes of Axonotmesis

Answer 5

Traction
Compression
Crush Injuries

Question 6

Neurotmesis

Answer 6

Most Severe Grade of injury to a peripheral nerve

[Axon, myeline, connective tissue components are all damage or transected]

• irreversible injury; there is no possibility of regeneration
• Flaccid paralysis and wasting of muscles occur with total loss of sensation to the are supplied by the nerve
• All motor and sensory loss distal to lesion are permanently impaired
• No spontaneous recovery, surgical intervention can be tried, with sensory recovery occuring before motor fibers