A child’s arm is bent when straightened, which may be related to deformity healing, dislocation, joint adhesion and other factors. 1. Deformity healing: children may not pay attention to the local alignment and alignment after the fracture, which may cause deformity healing in the arm area, so the arm appears to be bent when straightening. 2. Dislocation: Some children may dislocate their arms, resulting in a bent arm with obvious pain. 3. Joint adhesion: when the child has a straight arm is bent, but also need to be highly suspected and joint adhesion related, such as in the case of prolonged braking, will cause local soft tissue adhesion, so the above symptoms. The child’s arm is bent, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.