Question
Lesion of the marked structure (yellow arrow) of hand leads to which of the following
| A. |
Ape thumb deformity
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| B. |
Claw hand
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| C. |
Wrist drop
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| D. |
Claudication
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Show Answer
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Correct Answer � C
Explanation
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Answer: C. Wrist drop
* Marked structure is the radial nerve
* Lesion of the radial nerve leads to wrist drop
Wrist drop is a condition in which the wrist and the fingers cannot extend at the metacarpophalangeal joints. The wrist remains partially flexed due to an opposing action of the flexor muscles of the forearm. As a result, the extensor muscles in the posterior compartment remain paralyzed.
Types of wrist drop are distinguished by the nerves affected:
- The weakness of brachioradialis, wrist extension and finger flexion = radial nerve lesion
- The weakness of finger extension and radial deviation of the wrist on extension = posterior interosseous nerve lesion
- The weakness of triceps, finger extensors, and flexors = C7,8 lesion
- General weakness of upper limb marked in deltoid, triceps, wrist extension and finger extension = corticospinal lesion
