Repeated USMLE Questions Step 1- 202

A 20 year-old male athlete complains of pain and weakness of his right arm. He had a successful surgery on his knee last week. He has been walking with the aid of crutches since then. On examination, he is unable to extend his right arm at the elbow or the hand at the wrist. There is also a sensory deficit over the dorsolateral area of the right hand. Neurological examination is otherwise normal.

Which nerve is most likely related to his symptoms?

A-Axillary nerve

B-Median nerve

C-Radial nerve

D-Suprascapular nerve

E-Ulnar nerve

Answer





This is a typical presentation of radial nerve palsy caused by the compression of the crutches on the spiral groove of the humerus. Inability to extend the elbow and wrist drop is due to defective innervation of triceps, brachioradialis and small extensors in the dorsum of the hand. Sensory innervation to the dorsolateral area of the hand is also affected.

The correct answer is C