Shoulder Impingement Syndromes: State of the Art Imaging

Shoulder impingement syndromes include subacromial, subcoracoid, and internal impingement. Impingement is primarily a clinical diagnosis. However, multimodality imaging is essential for defining anatomy and excluding differential considerations. Understanding the mechanisms of shoulder impingement and the ways each imaging modality aids diagnosis and treatment planning is of paramount importance. This article will describe the current understanding of shoulder impingement syndromes with an emphasis on subacromial impingement in describing state of the art imaging.