The authors restate that simple pain of the shoulder, which is a form of scapulo-humeral periarthritis characterized by the existence of pain without limitation of movement, is almost always associated with lesions of the tendons of the short muscle teres of the shoulder. They term chronic simple pain of the shoulder the rare cases where, despite therapy that is reputed to be efficient, there is a gradual development lasting more than one year, either continuously or with relaps periods of less than three weeks. They show that these chronic shoulders are practically always associated with a rupture of the coat of the muscle teres or a calcification of the tendons of the teres coat. Ruptures are as much frequent in men as in women and calcifications definitely more frequent in women (60%). Before 30 years of age, the most frequent lesion is almost always a calcification, and after 65 rupture is more common. Between 30 to 65, the probability of a calcification in a chronic simple painful shoulder, goes from 100% to 0, while the probability of a rupture increases from 0 to 100%.