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    What's the reason for getting brisk reflexes, *******ity and stiffness in upper motor neurone lesions? Trying to understand it so I don't have to 'rote learn'
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    Primitive organisms without a significant CNS tend to have muscles that are more used for posturing and slower more primitive movements, so they tend to have very high tone. As the CNS developed it allowed more fine control, and as part of this created fibres (generally GABA medicate) to inhibit this tone.

    This is what you see in an upper motor neuron lesion. You lose that inhibition coming from above, and so the 'natural' tone of the muscle becomes apparent.

    Its similar to how you get flexor and extensor responses to pain (part of GCS) based on whether you're decortical or decerebrate
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    (Original post by nexttime)
    Primitive organisms without a significant CNS tend to have muscles that are more used for posturing and slower more primitive movements, so they tend to have very high tone. As the CNS developed it allowed more fine control, and as part of this created fibres (generally GABA medicate) to inhibit this tone.

    This is what you see in an upper motor neuron lesion. You lose that inhibition coming from above, and so the 'natural' tone of the muscle becomes apparent.

    Its similar to how you get flexor and extensor responses to pain (part of GCS) based on whether you're decortical or decerebrate
    Oh I see - that's actually very interesting, I didn't know about that.

    Also, how would you pick up a brisk reflex in an examination? I don't quite understand what is meant by the term.

    Thanks for your help!
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    (Original post by TeenToDoctor)
    Oh I see - that's actually very interesting, I didn't know about that.

    Also, how would you pick up a brisk reflex in an examination? I don't quite understand what is meant by the term.

    Thanks for your help!
    When you've done reflexes a few times, you'll start to notice if they are brisker. I take it to mean it is more apparant/ more pronounced.
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    (Original post by TeenToDoctor)
    Oh I see - that's actually very interesting, I didn't know about that.

    Also, how would you pick up a brisk reflex in an examination? I don't quite understand what is meant by the term.
    Their reflexes are more pronounced. The twitch is physically bigger.

    Sometimes you even get spreading of reflexes (e.g. you hit their ankle and the knee jerks too).
 
 
 

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