Remote spinal accessory nerve palsy as a cause for scapular dyskinesia in an adolescent baseball pitcher

Abstract

We report a case of anterior shoulder pain and atypical scapula dyskinesia in an adolescent baseball pitcher due to a chronic mild spinal accessory nerve palsy. The spinal accessory nerve innervates the trapezius muscle, which is responsible for scapular retraction during overhead throwing. Impaired trapezius function leads to anterior shoulder pain by a disruption of the kinetic chain at the level of the scapula. His pain was refractory to injections targeting the biceps tendon, arthroscopy, and focused scapular rehabilitation. This case highlights a less common case of scapular dyskinesia and anterior shoulder pain due to neurogenic causes in an overhead-throwing athlete.