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Which muscle shown in Figure A-E derives its innervation from the posterior cord of the brachial plexus?
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An 18-year-old football player is injured after making a tackle with his left shoulder. He has decreased sensation over the lateral aspect of the left shoulder and radial aspect of the forearm. Motor examination reveals weakness to shoulder abduction and external rotation as well as elbow flexion. He has decreased reflexes of the biceps tendon on the left side but full, nontender range of motion of the cervical spine. What anatomic site has been injured?
Fourth cervical nerve root
Upper trunk of the brachial plexus
Middle trunk of the brachial plexus
Lateral cord of the brachial plexus
A 26-year-old male sustains a traction injury to his left arm after a motorcycle crash with resulting weakness in this left upper extremity. An electromyography (EMG) done shows normal cervical paraspinal muscle activity. Which of the following statements is true regarding this injury?
The injury has likely resulted in the avulsion of several nerve roots
Physical exam would likely reveal drooping of his left eyelid and anhidrosis
Intact paraspinal musculature on EMG is suggestive of a post-ganglionic lesion
Immediate surgical intervention with neurotization would eliminate weakness and restore function
The patient would show a normal histamine test
A 21-year-old collegiate football player has been diagnosed with a left superior trunk brachial plexus injury following a tackle. Which of the following would most likely be normal on physical exam?
Sensation over the lateral aspect of shoulder
Sensation over radial aspect of forearm
2nd and 5th finger abduction
A patient sustains a transection of the posterior cord of the brachial plexus from a knife injury. This injury would affect all of the following muscles EXCEPT?