In the middle of the front chest, on both sides of the sternum is where the ribs and rib cartilage are located. If the ribs or rib cartilage on both sides are not the same height, the following reasons may exist: 1, genetic factors are a common cause of this condition, some people are born with different heights of the ribs on both sides, but the height does not vary much, and without careful examination, it is usually difficult to be found and there are no other symptoms of discomfort or special performance; 2, This symptom may also occur if you often do heavy physical exercise or training, especially if you are used to using one limb for exercise. In the process of exercise inevitably cause slight damage to one limb, easily cause the symptoms of one side of the ribs, rib cartilage protrusion, this will not have other uncomfortable symptoms; 3, there are also some scoliosis adolescents, there must be different heights of the two sides of the thorax performance, because the scoliosis of the spine pulling role, making the two sides of different heights. When this symptom occurs, it is best to have a timely radiological examination to prevent the symptoms from worsening; 4. There is also the relatively rare case of a local tumor, which makes the two sides of the sternum not the same height.