Review Question - QID 213017

A 23-year-old professional rower presents with pain over the radial wrist when pronating and supinating his forearm. He denies any recent history of trauma and reports that the pain has been worsening over the past few months. On physical examination, there is crepitus over the distal forearm with wrist and thumb extension. Which of the following matches the correct extensor tendon compartment with the structures most likely affected in this pathology?