<prompt> A physician notes weakness of a patients thumb in extension, although rotation, flexion, abduction, adduction, and opposition are normal. Which of the following nerves is most likely involved?Median and radialMedian and ulnarMedian onlyRadial only  <response>: All three of the nerves listed innervate muscles that supply the thumb. Extension is provided by the extensors pollicis longus and brevis, which are innervated by the radial nerve. Ref: Maheshwari 6e pg 63,65. 