Nerve Injuries In The Lower Limb Flashcards
What is the term for a spinal cord injury?
Myelopathy
What is the term for a spinal nerve root injury?
Radiculopathy
What is the term for a Peripheral nerve injury?
Peripheral Neuropathy
What affect does Myelopathy have on the body?
No communication (paralysis) below point of damage
What affect does Radiculopathy have on the body?
Only affects specific Dermatome and myotome supplied by the spinal nerve root
What affect does Peripheral Neuropathy have on the body?
Loss of that specific nerves function
What are the 4 S’s for describing the ways nerves can become damaged?
Stretched (“Traction”)
Squashed (“Compressed”)
Severed (“Laceration”)
Stressed (By medical conditions)
Briefly, what is the structure of a nerve?
Axon
Surrounded by Endoneurium
Many parallel axons surrounded by perineurium to form a fascicle
Many fascicles surrounded by Epineurium forms the nerve
What are the 3 classifications of nerve injury in Seddon Classification?
Class I = Neuropraxia
Class II = Axonotmesis
Class III = Neurotmesis
What is Wallerian degeneration?
The degeneration of axons distal to an injury
What is Class I Neuropraxia nerve injury?
Temporary physiological block of conduction along axon
No disruption to nerve structure (NO Wallerain degeneration)
ENDO/PERI/EPIneurium intact
What is the recovery like for Neuropraxia?
FULL recovery in days-weeks
Mildest form of nerve damage
What is Class II Axonotmesis?
Axons divided
Axon and myelin sheath disrupted (Wallerian degeneration)
EPI/PERI/ENDOneurium still intact
What is recovery like from an Axonotmesis injury?
Axon regeneration can occur
Don’t normally need surgery
Recovery time depends on the cut axons distance from target site
What is Class III Neurotmesis?
Partial or full disruption to the nerve structure (ENDO/PERI/EPI and axons)
Wallerian degeneration
What is recovery like for a Neurotmesis injury?
Needs surgery since scar tissue between the divided fascicles prevents regeneration
What cells guide the direction an axon regenerates in?
Schwann cells
In an intervertebral disc prolapse/herniation, which direction does this normally happen?
Paracentrally
Which nerve is typically affected with a paracentral disc herniation?
Traversing root
What is the traversing root?
So at the L4-L5 level L4 is the exiting root
L5 is the traversing root
What does Iatrogenic injury mean?
Injury caused by doctor intervention (surgery may damage a nerve)
What are the ways that the Femoral nerve can be damaged?
Direct trauma
Iatrogenic
Nerve blocks
What are the 2 branches of the femoral nerve
Anterior femoral cutaneous nerve
Saphenous nerve
Where does the femoral cutaneous nerve inveterate?
Anteromedial thigh
Where does the saphenous nerve supply?
Medial leg
Where does the femoral nerve branch into the saphenous nerve?
Quite high up in the femoral triangle
What is the motor function of the femoral nerve?
Hip Flexion
Knee extension
What muscles does the femoral nerve innervate?
Quadriceps:
Rectus femoris
Vastus medialis/intermedius/lateralis
Sartorius
If the femoral nerve is damaged will hip Flexion be weakened or absent and why?
Weakened
Other muscles like Iliacus, Pectineus and psoas major are hip flexors and have other innervations
However, these muscles are mainly innervated by the femoral nerve
If the femoral nerve is damaged will knee extension be weakened or absent and why?
Absent
All the muscles which extend the knee supplied by femoral nerve
How can the sciatic nerve be damaged?
Compression in gluteal region (Piriformis syndrome)
Iatrogenic (IM injections)
Direct trauma like posterior hip dislocation
What is Piriformis syndrome?
The sciatic normal emerges inferior to piriformis or sometimes between piriformis
If the piriformis has spasms it can compress the sciatic nerve
Why can the sciatic be damaged with a posterior hip dislocation?
Sciatic close to femur