au3s

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A 42 year old man has 2 weeks history of pain in the right side of the neck that radiates down the lateral aspect of the right arm to the 3rd digit. He 1st noted the pain after lifting his 5 year old son. He has also had mild weakness of the right arm and tingling in the right 3rd digit. He words as a computer programmer, and spends most of the day at a keyboard. Exam shows mild weakness of the right elbow and wrist extension, and a decreased right triceps reflex. Sensory exam shows no abnormalities. Which of the following is the most likely location of the lesion causing this pt’s symptoms.

a) Brachial plexus

b) cervical nerve root

c) cervical spinal cord

d) median nerve

e) radial nerve

f) thoracic nerve root
 
Aug 9, 2014
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I would lean towards this too...so C?
B. Nerve root. Spinal cord would have signs at all levels below the lesion, not just in the distribution of C7 and C8.

I have to agree but how can we rule out brachial plexus lesion? Based on no sensory deficits?
Honestly when I saw this I immediately thought C7-C8 because it was one of the things we learned in neuro a few weeks ago. I just looked at brachial plexus (to answer your question) and I don't think it's likely to get a lesion within the plexus that affects C7-C8 without also hitting C5 or C6 or T1. There's no problems with elbow flexion (C5) and the only finger with problems is the middle finger (C6 is fine) and no sensory loss as you mentioned (so T1 is fine).
 
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au3s

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So whats the difference btw brachial plexus injury vs root injury?
 
Aug 9, 2014
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So whats the difference btw brachial plexus injury vs root injury?
Not really sure of how to answer this.. Brachial plexus is roots, trunks, divisions, cords, branches. Roots are roots.
 
Apr 24, 2012
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So whats the difference btw brachial plexus injury vs root injury?
What seminoma said. The spinal nerve root lesions (radiculopathies) will be very specific in their distributions and follow dermatomal patterns. A brachial plexus lesion is further downstream and occurs after a mixing of the nerve roots so there will likely be a plethora of nerve root distributions affected.

Ex. C7/8 radiculopathies affect everything in the C7/C8 distribution. A brachial plexus lesion involves many different nerve roots including C5-8, and T1.