Baby arm dislocation, also known as radial tuberosity subluxation, can appear pain, dysfunction and other symptoms. 1. Pain: when radial tuberosity subluxation occurs, the child often feels pain in the elbow, and the pain is obvious when pressing, and when checking, the lateral elbow often has obvious pressure pain. 2. Functional disorders: the child’s upper limb is often in a semi-flexed position and rotated forward position, due to pain, the child is often afraid to move the affected limb, refusing to extend or flex the affected limb, and afraid to rotate the upper arm. Radial tuberosity subluxation in babies is usually caused by external pulling or violence. 2~5 years old, young children’s bones and ligaments are not yet fully developed, and external pulling can easily lead to radial tuberosity subluxation. When symptoms such as pain and dysfunction occur, it is recommended to go to the hospital.