This issue has not come up in an exam, as yet (at least not since 2000).
However, it may well appear one day. Radial nerve injury is a common complication of major traumatic humeral fracture.
For a reference, I direct the time-rich reader to Sir Sydney Sunderland's "Nerves and Nerve Injuries", from 1968. (Not available as full text in Google, unfortunately.)
For brachial plexus injuries, I recommend Alain Gilbert's book.
For peripheral nerves, there is Haymaker, Webb, and Barnes Woodhall. Peripheral nerve injuries: principles of diagnosis. Thieme, 1998.
Vanderpool, D. W., et al. "Peripheral compression lesions of the ulnar nerve."Journal of Bone & Joint Surgery, British Volume 50.4 (1968): 792-803.