Upper extremity muscle function and innervation 02
Topic: Anatomy
Created on Monday, August 18 2008 by jdmiles
Last modified on Monday, August 18 2008.
During a needle EMG, you notice a large number of fibrillations in the abductor pollicis brevis muscle while the patient is at rest.
From this, you deduce that the patient has a lesion. Of the following options, which lesion is most compatible with the EMG findings?
A) A lesion in the lower trunk B) A lesion in the ulnar nerve C) A cervical spinal cord lesion D) A lesion in the radial nerve E) A lesion in the posterior cord
This question was created on August 18, 2008 by jdmiles.
This question was last modified on August 18, 2008.
ANSWERS AND EXPLANATIONS
A) a lesion in the lower trunk
This answer is correct.
The fibrillations suggest an active peripheral nerve lesion. The abductor pollicis brevis muscle receives innervation from the median nerve, the medial cord, the lower trunk, and the C8 and T1 nerve roots. (
See References)
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B) a lesion in the ulnar nerve
This answer is incorrect.
The fibrillations suggest an active peripheral nerve lesion. The abductor pollicis brevis muscle receives innervation from the median nerve, the medial cord, the lower trunk, and the C8 and T1 nerve roots. (
See References)
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C) a cervical spinal cord lesion
This answer is incorrect.
The fibrillations suggest an active peripheral nerve lesion. The abductor pollicis brevis muscle receives innervation from the median nerve, the medial cord, the lower trunk, and the C8 and T1 nerve roots. (
See References)
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D) a lesion in the radial nerve
This answer is incorrect.
The fibrillations suggest an active peripheral nerve lesion. The abductor pollicis brevis muscle receives innervation from the median nerve, the medial cord, the lower trunk, and the C8 and T1 nerve roots. (
See References)
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| | |
| | |
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E) a lesion in the posterior cord
This answer is incorrect.
The fibrillations suggest an active peripheral nerve lesion. The abductor pollicis brevis muscle receives innervation from the median nerve, the medial cord, the lower trunk, and the C8 and T1 nerve roots. (
See References)
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| | |
| | |
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References:
1. Preston, D.C., and Shapiro, B.E. (2005). Electromyography and Neuromuscular Disorders: Clinical-Electrophysiologic Correlations, 2nd Edition. Elsevier, Philadelphia. (ISBN:075067492X) | Advertising:
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anatomy
Upper extremity muscle function and innervation 02
Question ID: 081808096
Question written by J. Douglas Miles, (C) 2006-2009, all rights reserved.
Created: 08/18/2008
Modified: 08/18/2008
Estimated Permutations: 198000