The left rib protrusion may be caused by these factors: 1. rickets due to calcium deficiency, manifested as a rib bead with no specific local discomfort, but accompanied by calcium deficiency symptoms such as relatively slow growth and muscle spasms. 2. costochondritis, due to cold, strain, etc., resulting in a sterile inflammatory reaction of the rib cartilage, mostly manifested as local pain and swelling at the same time. 3, The fracture of the ribs, since the fracture of the ribs has occurred, localized due to the proliferation of bone scabs, manifests itself as a hard swelling that is clearly protruding, mostly without special discomfort. 4, tumor lesions, localized occupational changes in the ribs, the surface can be palpable or clearly protruding, localized can manifest itself as obvious pain and progressive aggravation, once there is a clear protrusion of the left rib, you need to go to the orthopedic department of the hospital, through chest radiographs Once the protrusion of the left rib is obvious, you need to go to the orthopedic department of the hospital to clarify the specific cause through chest radiography and other examinations.