Sonographic detection of radial nerve entrapment within a humerus fracture

Radial neuropathy is frequently associated with fracture of the middle third of the humerus owing to the course of the nerve adjacent to the humeral shaft. The prevalence varies from 2 to 18% of humeral fractures. The therapeutic management is still controversial. Some authors recommend initial surgical exploration, whereas others prefer observation and intervention only if the injured nerve failed to recover after a period of more than 4 months. According to the literature, verification of an entrapped radial nerve in a fracture gap requires surgical exploration, but diagnostic tools to verify the existence of a pathologic condition are limited. We describe the sonographic findings of an entrapped radial nerve and review the literature regarding diagnosis and treatment of entrapped radial nerve in cases of humeral fracture.