Enlargement of the sternal raphe may be due to poor fracture healing, cartilage inflammation, cancer metastasis and so on. 1. Poor fracture healing: the patient has a history of sternocleidomastoid fracture, which may be improperly treated, triggering the abnormal healing of the sternocleidomastoid, which will lead to the excessive generation of local bone scabs, thus causing the sternocleidomastoid protrusion to increase in size. 2. Inflammation of cartilage: the area of raphe will gradually change from cartilage to bone tissue with the development of the body, and before it is completely changed into bone tissue, if there is long-term inflammation of the cartilage in this area, it may lead to stimulation of the raphe, which may cause the abnormal enlargement of the raphe. 3. Cancer metastasis: when malignant tumors metastasize to the area of raphe, it will also lead to the enlargement of raphe. Abnormal enlargement of sternal raphe may also be due to other reasons, which should be examined and treated in hospital in time.