Objective: The diagnosis of denervation injury as a cause of shoulder pain is conventionally based on clinical findings and electrophysiologic studies. MRI has an important role in identifying direct and indirect signs of neuropathy and can confirm the presence of nerve compression, depict space-occupying lesions, and exclude other intrinsic lesions of the shoulder. In this article, the relevant anatomy, causes, clinical features, and MR appearances of nerve injury and muscle denervation of the shoulder girdle are presented.
Conclusion: MRI is commonly performed in patients with shoulder pain of uncertain origin and can determine the morphologic cause, precise location, and duration of nerve injury and muscle denervation. Knowledge of the relevant anatomy, cause, and clinical and imaging findings is important in making a potentially treatable diagnosis, avoiding confusion with inflammatory or neoplastic processes, and obviating biopsy or surgical intervention.