EMG 1

Card Set Information

Author:
shmvii
ID:
239782
Filename:
EMG 1
Updated:
2013-10-09 17:25:51
Tags:
EMG
Folders:

Description:
EMG
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user shmvii on FreezingBlue Flashcards. What would you like to do?


  1. whne stimulating a normal muscle with electric stim, what are electrodes actually stimulating?
    • motor branch as it enters the area of the muscle
    • (not the nerve root, peripheral nerve, or the muscle directly)
  2. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has ataxia
    yes bc it's CNS involvement while PNS is fine
  3. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has POLIO
    no, because the ant horn cell (PNS) is hit
  4. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has COMPLETE SCI
    yes (though not if it's cauda equina)
  5. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has SPINAL MUSCULAR ATROPHY
    no bc muscle is gone
  6. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has HEMIPLEGIA
    yes
  7. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has PARTIAL NERVE INJURY
    yes
  8. will neuromuscular electric stim with sort duration current produce a response if the pt has lost all vol control and has COMPLETE NERVE INJURY
    no (but wait 14 days bc by then the degen will have fully occured so you'll know what's actually in tact)
  9. reaction of degeneration (RD)
    when? what's it testing?
    at least 10-14 days after injury so you'll get the full degen

    tests how the motor unit responds to AC and DC stim
  10. in RD the 4 responces for AC stim of 60 pulses / second
    normal RD - tetanic contraction

    partial RD - diminished response

    full RD - no response

    absolute RD - no response
  11. what's it mean if there's a normal RD
    no RD -- motor axon is intact, no degen, but there may be a neuropraxia

    if you get a normal (tetanic contraction) response on AC, no need for DC
  12. what's it mean if there's "partial RD"
    it's immediately after an injury and degen isn't complete

    partial nerve injury
  13. what's it mean if there's full RD?
    • loss of excitablility of muscle
    • muscle is nevervated
  14. what's it mean if there's absolute RD?
    • loss of excitability of nerve and muscle
    • total connective tissue proliferation (most likely the fibers near the stimulator have turned to fiber or fat)
  15. in RD the 4 responces for DC stim
    normal RD: brisk twitch

    partial RD: diminished response, sluggish contraction

    full RD: slow, sluggish response

    absolute RD: no response
  16. RD in UMNL, LMNL, tendon laceration?
    • UMNL - normal
    • LMNL - present/impaired
    • laceration - normal (the muscle will activate and shorten, just won't produce a motion bc it's not attached
  17. disadvantages of RD testing
    • misses minor changes
    • false -'s with deep injuries to muscle or nerve (so it's best for sup muscles)
    • false severe +'s with superficial injuries
    • doesn't give a reason for the abnormality
  18. nerve conduction & EMG, via conduction velocity gives info on ....
    status of each peripheral nerve -- myelination + MU innervation
  19. nerve conduction & EMG, via amplitude of responses gives info on ....
    status of the total compliment of nerve axons intact (low amplitude = some axons are damaged)
  20. what do K+ and Ca+ ions do to the potential of a nerve membrane 
    makes the inside -70, which is more positive than the outside's -90 mV
  21. what does a stim do to a nerve membrane's potential?
    raises it ~110 mv to +40 mV, making it much higher than the outside, setting up the AP to run along the axon
  22. MEPP
    • miniature end plate potential
    • sub threshold release of ACh -- occurs constantly in a healthy NMJ
    • when they exceed threshold, that's when you get an AP
  23. how much ACh in a synaptic vesicle at an axon terminal?
    10,000 quanta
  24. steps in the NMJ for an AP and muscle contraction
    • Ach crosses NMJ
    • bonds w post-synaptic receptors and reacts with them
    • AP goes into transverse tubular system
    • triggers sarcoplasmic reticulum to release Ca++
    • 5-10 msec later, relaxation and reuptake of Ca++
  25. which comes first, the sensory or motor disturbance?
    sensory!

    (and it's a chicken tree before a chicken)
  26. mononeuropathy vs mononeuropathy multiplex vs polyneuropathy vs radiculopath
    • mononeuropathy: 1 nerve affected
    • mono multiplex: 1, then another, then more, BUT random nerves with no pattern
    • poly: multiple, and they're related
    • radic: it's radiating?
  27. 3 (of the many) etiologies of neuropathies
    diabetes, trauma, vitamin deficiency
  28. names & descriptions of types 1-5 nerve injury classifications
    • I - neurapraxia - blockage w/o damage to axon (leg falling asleep, early CTS)
    • II - axonotomesis - Wallerian degen w axonal damage but sheaths intact. Conduction ends asap, but likely recover
    • III - neurotmesis w damage to internal sheaths
    • IV - neurothmesis w severe internal damage & scarring
    • V - neurotmesis  - complete nerve transection
  29. how will mild demyelination affect the EMG?
    • delayed conduction of the sensory nerve AP
    • slight decrease in amplitude of response
  30. how will advanced demyelination affect the EMG?
    • delayed conduction in sensory and motor fibers
    • moderate decrease of amplitude
  31. how will demyelination w axonal degen affect the EMG?
    • considerable delay in coduction
    • greater attenuation of evoked responses
  32. how will total axonal degen affect the EMG?
    no conduction occurs

What would you like to do?

Home > Flashcards > Print Preview