Patients with shoulder drowsiness, understood as shoulder weakness, generally most commonly have rotator cuff injuries. Rotator cuff injury is mainly due to the degeneration of the rotator cuff, a tear has occurred, or due to the acute movement of the acute injury, tear occurred. The rotator cuff is the power machine of shoulder abduction. If the rotator cuff is torn, there will be weakness in shoulder abduction, especially in lifting up, which is what the common people say is the situation of shoulder sleepiness and weakness. In such a case, the patient must undergo an early MRI examination, to clarify the damaged part of the rotator cuff and the degree of damage. If a complete tear is found, the rotator cuff should be repaired with the assistance of shoulder arthroscopy to re-establish the power of the rotator cuff.