This paper examines a case of radial nerve palsy in a 13-year-old girl caused by nerve embedded in a humeral shaft fracture. An X-ray showed a mild angular-displaced humeral shaft fracture. Two weeks later, an intramedullary Ender nailing was performed. Because of brain injury due to traffic accident, the patient lost consciousness for one month. Once she regained consciousness, radial nerve palsy was discovered and closely observed. As the radial nerve palsy had not healed after five months, the radial nerve was explored and found to be interposed between fracture sites and totally entrapped in the fracture callus. During surgery, both the proximal and distal ends of the radial nerve were cut at the surface of the humeral bone. Then, the radial nerve stumps were end-to-end sutured because of their enough length. One year after surgery, the radial nerve palsy had completely recoverd.