Radial Motors

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PMR 4 MSK

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I've been trying to do more radial motors, mostly for practice for when I need them. I've used both surface and needle pickup in/over the EIP. I stim 8 cm proximal, then antecubital fossa (ACF), below the spiral groove and above. I've noticed the following -

Usually takes 100 mA and 200 mSec to get full activation for distal stim, which blows the onset curve to hell. Often takes 300 mSec + proximally. Most onsets seem to be around 2.0 - 2.8 ms.

Antecubital and other proximal stims give large postive deflection before the rise, making onset difficult again.

Distal stim amplitude is usually around 3 - 4 mV, proximal 2 mV, sometimes 1-2 mV. Proximal from ACF and back are usually about 1/2 distal stim amplitude.

Measuring seems to be a bitch - even with arm fully extended, I often get NCV in the proximal forearm in the 45 m/s range - like the measurement is off by a couple cm. Similarly, below SG to ACF gives values around 75 - 80 m/s often, even using surface tape measure. It's like my stim point compared to what I'm measuring in the ACF is off by 2-3 cm consistantly.

I've done some Erb's point stims and almost never get a response above 1 mV, if any.

I also have checked for F-waves, and find them in about 25% of those tested. They're short and fat when they are there.

I've read Dumitru's views on radial nerves, and several other authors. Any comments? Others' experiences with radial motors? Tips?

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