1. In a series of one hundred personal cases of "painful shoulder" rupture of the musculotendinous cuff was proved by operation in eighteen cases and was presumed in eight further cases, namely, in about one quarter of the series. 2. Of the eighteen cases treated by operation through the transacromial approach, perfect results were obtained only in four. The other results were unsatisfactory. In five, movement was good but there was pain or weakness of the limb. In nine the condition was unaltered or made worse. 3. Conservative treatment of traumatic lesions of the supraspinatus tendon is therefore advocated. The advisability of rest of the shoulder joint in an abduction splint for five or six weeks is stressed. Operative exposure, through a transacromial approach, is recommended only when conservative measures have failed. 4. When there is rupture of the cuff there is evidence that simple longitudinal suture of the gap after freshening of the margins is likely to give better results than attempts to suture the medial end of the rupture to the greater tuberosity. Most ruptures have a longitudinal extension of the initial transverse tear, and direct suture of the medial edge of the gap to the greater tuberosity may lead to shortening of the tendon and interference with its function. 5. Ruptures of the supraspinatus tendon may cause no symptoms, lead to complete loss of function, or cause a painful arc of movement during mid-elevation. The clinical state depends upon whether or not the condition of the ruptured tendon is causing pain, and whether the other short rotator muscles of the shoulder can compensate in tensor and fixator actions for the loss of action of the supraspinatus. 6. Capsulitis is a convenient term by which to describe inflammatory lesions of the capsule and bursae around the shoulder joint. The initial stage of irritative capsulitis may develop to the later stage of adhesive capsulitis. Differentiation is important because treatment in the first stage is by rest, and in the second by manipulation and exercise. 7. The subdeltoid bursa is the "peritoneum" of the spinatus tendons; like the peritoneum it shares the pathology of the organs it protects and is itself seldom the site of primary pathological processes. 8. The management of the "frozen shoulder," whether loss of movement is protective or adhesive, calls for time and patience but the ultimate outlook is good.