Peripheral Nerve Injuries Flashcards
Axons are covered with what?
Endoneurium
Fascicles are covered with what?
Perineurium
Nerves are covered with what?
Epineurium
What are the main causes of nerve injuries?
Compression
Trauma
What are the classical conditions of nerve compression?
Carpal tunnel syndrome
Sciatica
Morton’s neuroma
What is Morton’s neuroma?
Digital nerve in 2nd/3rd web space of forefoot
What is neurapraxia?
Stretched/bruised nerve
Reversible conduction block
Local ischaemia/demyelination
What is axonotmesis?
Endoneurium intact with disruption to axons
Stretched or crushed
Wallerian degeneration
What is neurotmesis?
Complete nerve division
Laceration or avulsion
No recovery unless repaired
Poor prognosis
What are the main types of nerve injury?
Neurapraxia
Axonotmesis
Neurotmesis
What are closed nerve injuries?
Nerve injuries in continuity
neuropraxis, axonotmesis
When is surgery indicated in closed nerve injuries?
After 3 months
What are open nerve injuries?
Complete break in nerve continuity
What is the typical cause of nerve division?
Laceration
What happens to distal segments of lacerated nerves?
Wallerian degeneration
up to 2/3 weeks after injury
What are the symptoms of nerve injury?
Dysaesthesia Weakness/paralysis Wasting Dry skin Diminished reflexes
Which modality of nerve function returns first in nerve healing?
Pain sensation
What is Tinel’s sign? What is its function?
Monitoring recovery
Tap over nerve site
Parasthesia as far distally as nerve regeneration has progressed
How is nerve injury monitored?
Tinel’s sign
Nerve conduction studies
What is the peripheral nerve injury “rule of 3”?
Clean/sharp injuries - surgery within 3 days
Blunt injuries - surgery within 3 weeks
Closed injuries - within 3 months
