It is not normal for the left side of the rib cage to be more convex than the right side. The causes of this condition are related to local tissue abnormalities, and common causes include congenital development, costochondritis, osteochondroma, and old rib fractures. 1. Congenital development: Bilateral rib asymmetry caused by congenital development will result in the corresponding condition, which usually does not cause any symptoms. 2. Osteochondritis Dissecans: Osteochondritis Dissecans leads to thickening and swelling of the surrounding soft tissues, which will cause corresponding manifestations. 3. Osteochondroma: Osteochondroma protrudes outward, which can also cause the corresponding condition. 4. Old fracture: old fracture, resulting in local bone irregularity, will cause the corresponding conditions. The specific situation needs to be combined with clinical examination to make a comprehensive judgment, once there is a local protrusion accompanied by obvious pain and discomfort, it is necessary to consult a doctor in time for observation and standardized treatment under the guidance of the clinician.