Ultrasonographic Evaluation and Feasibility of Posterosuperior Internal Impingement Syndrome: A Case Series.

UNLABELLED: Posterosuperior impingement (PSI) is an underdiagnosed cause of posterior shoulder pain and should be differentiated from classic and external impingement. PSI involves the internal impingement of soft tissues, including the undersurface of the rotator cuff against the posterosuperior labrum when the arm is brought into abduction and external rotation (ABER). Ultrasonography (US) can be useful in the assessment of PSI because of its high resolution and ability to perform during dynamic maneuvers in ABER. This series of 3 cases illustrates the feasibility of US in the evaluation of PSI when the history and physical examination implicate this condition.

LEVEL OF EVIDENCE: V.