Tears of the rotator cuff are one of the most common injuries to any tendon in the human body. Various theories and observations have since been made as to the origin of these tears. It is now commonly accepted to distinguish between"extrinsic" and"intrinsic" causes. Extrinsic describes an attrition which might have been caused by a subacromial bony conflict, while intrinsic changes originate within the tendon body itself due to age-related degenerative changes, giving rise to partial and later complete rupture of the tendon body. A better understanding of the underlying pathophysiological mechanism will make it easier for the attending orthopedic surgeon to decide whether a more conservative or operative course will have the best outcome for the situation given.