Shoulder: Rotator cuff and impingement syndromes

Abstract

Impingement syndromes are a group of abnormalities characterized by shoulder pain with the arm in certain positions, and can be divided into external and internal categories. External impingement is caused by structural changes outside of the joint and is classified as primary, secondary and subcoracoid types. Internal impingement is secondary to rotator cuff and capsular dysfunction, and is subdivided into posterosuperior (classic internal impingement), anterosuperior, anterior and entrapment of the long head of the biceps tendon subtypes. The role of imaging is to demonstrate structural findings that can corroborate a clinical impression of impingement or demonstrate findings that are suggestive of impingement, but the diagnosis of an impingement syndrome is always clinical.