What is this limited bulging of the left side of the ribs at age 13?

The 13-year-old limited bulging of the left side of the ribs may be related to strain and contusion, but also may be related to factors such as bone tumors.
1. Strain and contusion: if the child usually has excessive labor or physical activity during exercise, it may lead to strain or contusion of the soft tissues of the left side of the rib cage.
2. Bone tumor: 13-year-old patients with the above symptoms may be related to bone tumors, bone tumors are tumors occurring in the bone or its collateral tissues, the clinical symptoms are manifested in the local expansion, pressure pain and so on.
The 13-year-old left side of the rib cage limited expansion, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.