Review Question - QID 210651

A 61-year-old woman presents to the emergency room with right hand pain and numbness. She was jogging around her neighborhood when she tripped and fell on her outstretched hand 3 hours prior to presentation. She reports severe wrist pain and numbness along the medial aspect of her hand. Her past medical history is notable for osteoporosis and gastroesophageal reflux disease. She takes omeprazole. She has a 10-pack-year smoking history. She has severe tenderness to palpation diffusely around her right wrist. She has decreased sensation to light touch along the palmar medial 2 digits. Sensation to light touch is normal throughout the palm and in the lateral 3 digits. When she is asked to extend all of her fingers, her 4th and 5th fingers are hyperextended at the metacarpophalangeal (MCP) joints and flexed at the interphalangeal (IP) joints. Which of the following nerves is most likely affected in this patient?