There are several common causes of a bone bulge in the middle of the sternum: first, it may be caused by calcium deficiency, which is one of the important elements for the normal growth and development of bones, and if calcium deficiency may lead to deformed bone growth, resulting in a bulging sternal bone. If it is caused by calcium deficiency, it can be treated by increasing the intake of calcium, you can eat foods with high calcium content, such as soy products, milk and eggs, etc. You can also take calcium supplements and vitamin D, and get more sunlight to promote the absorption of calcium in the body. Secondly, it may be caused by the misalignment of the sternal bones, if it is caused by misalignment, you should go to the hospital to take pictures to find out the specific situation, and can be treated by the method of manual reset, if the manual reset is not able to recover, you should consider surgery for treatment.