The causes of bone cortical thickening include physiological, bone cortical thickening disorder and sclerosing osteomyelitis, etc. There may be no obvious discomfort symptoms, fever, pain with localized swelling, etc. 1. Physiological: some special sports, such as Taekwondo, etc., often stimulate the bone cortex when exercising, so that the bone cortex is thickened by the stimulation, and there is generally no obvious discomfort symptoms. 2. Bone cortex thickening: generally common in infants, there may be irritability and fever, pain in the affected area with localized swelling. 3. Sclerosing osteomyelitis: there may be localized swelling or discomfort, as well as tenderness. Bone thickening may also have other causes of discomfort, should be timely to the regular hospital, the doctor according to the specific condition to determine the cause of the disease, for the cause of the correct treatment.