Peripheral Nerve Injuries Flashcards
What are peripheral nerves involved in?
Signal transmission between the spinal cord and body.
Name the three connective tissue coverings of peripheral nerves.
Endoneurium, perineurium, epineurium.
What components make up a peripheral nerve?
Nerve fibers, connective tissues, and blood vessels.
What characterizes a peripheral nerve fiber?
Axon, neurolemma, endoneural connective tissue.
Which cells are crucial in the peripheral nervous system?
Neuronal, glial, stromal cells.
What do Schwann cells contribute to?
Myelination and support in peripheral nerves.
What is neuropraxia?
Temporary conduction block without axonal damage.
How does axonotmesis differ from neuropraxia?
Axonal damage occurs, connective tissue remains intact.
What defines neurotmesis?
Complete nerve severance and sheath damage.
What is the prognosis for neuropraxia?
Full recovery within days to weeks.
What process enables recovery in axonotmesis?
Axonal regeneration, up to one inch per month.
What is a traumatic neuroma?
Painful thickening due to nerve regeneration.
What are common symptoms of neurotmesis?
Pain, dysesthesias, complete motor/sensory loss.
Name three mechanisms of peripheral nerve recovery.
Wallerian degeneration, axonal regeneration, reinnervation.
What triggers Wallerian degeneration?
Axonal damage or severance.
How does compression injury typically manifest?
As neuropraxia, often short-term.
What is ‘double crush syndrome’?
Increased susceptibility to neuropathy from multiple lesions.
What is the main role of glial cells in PNS?
Support and protection of neurons.
How long does motor unit collateral branching continue post-injury?
3-4 months.
What characterizes sensory deficits in peripheral nerve injury?
Poorly localized, non-specific pain.
What factors influence axonal regeneration speed?
Distance from the injury site.
What type of injury leads to burner/stinger syndrome?
Traction injuries of peripheral nerves.
Which nerves are frequently injured in fractures?
Radial, common peroneal, axillary nerves.
What are common sites of compression injuries?
Narrow anatomical openings.
How does ischemia affect nerve function?
Causes conduction block due to lack of blood supply.
Which classification describes the mildest form of nerve injury?
Neuropraxia.
What leads to chronic pain in peripheral nerve injuries?
Incomplete recovery and traumatic neuromas.
What is the function of motor neurons in peripheral nerves?
Convey signals to muscles for movement.
What is the role of sensory neurons?
Transmit sensory information to the brain.
What distinguishes autonomic neurons in peripheral nerves?
Regulation of involuntary bodily functions.
