There are several possible causes for children and adolescents to have protruding ribs: first, the ribs on the lowermost edge of both sides show symptoms of exostosis, where the entire rib cage is protruding in appearance, and the protruding symptoms gradually disappear as the horizontal position of the chest rises, a condition also called rib exostosis, which is a natural phenomenon experienced by most people during their growth and development. This is mainly due to the fact that the ribs usually finish developing around the age of 25, and some of them are cartilage before the age of 25, while some of them have turned into hard ribs, resulting in protruding ribs due to the inconsistent elasticity and shape. Secondly, if there is a single swelling and protrusion of one side of the ribs, it may be due to a malformation of cartilage development or a local benign bone tumor, which requires prompt consultation at a regular hospital. Thirdly, if there is a bead-like protrusion of the rib cage, it is likely to be caused by vitamin D deficiency, which may lead to rickets.