Review Question - QID 218085

A left hand dominant 6-year-old boy who recently moved to the United States with his family presents to your clinic with a chief complaint of hand weakness. He describes an inability to firmly hold a pencil at school. He previously had a surgical procedure done on his hand in his native country, and his mother brings an X-ray of his hand prior to surgery, which is shown in Figure A. Examination of his hand demonstrates a well-healed surgical scar over the ulnar side of his thumb. What additional physical exam finding would be expected on his exam?