Most of the cases are caused by osteochondroma, osteomalacia, malunion of calf fracture, osteosarcoma and so on, and the specific causes of the disease should be examined and confirmed by the hospital in time. 1. Osteochondroma: when the growth of bones in the body is abnormal, it will cause multiple bony masses, resulting in the symptoms of bumps on the calf bone, and may also be accompanied by pain, fracture, deformity, limb dysfunction and other symptoms. 2. Osteomalacia: when bone spurs appear bony protrusions in the process of self-repair, it will cause the phenomenon of bumps on the calf bone, and some patients may also have joint pain, abnormal motor function and other symptoms. 3. Malformation healing of calf fracture: when there is a fracture on the calf bone, malformation changes occur during the healing process, which may lead to the phenomenon of bumps on the bone. 4. Osteosarcoma: when the calf area is affected by viral infection, ionizing radiation, gene mutation and other factors, causing abnormal cell proliferation, it may lead to the phenomenon of bumps on the calf bone, and will be accompanied by different degrees of persistent pain and other symptoms. There are many reasons for the symptoms, when symptoms appear, it is recommended to go to the hospital in time for examination and diagnosis, and carry out regular treatment as soon as possible to avoid the impact on the body.