Bone metastasis is usually found in the spine, ribs, pelvis and other locations, and it needs to be analyzed comprehensively with the primary tumor site. 1. Spine, the blood supply of human spine is relatively rich, and there are also many lymphatic systems, so the cancer cells can easily be transferred to the spine through the blood and lymphatic systems, and cause damage to the vertebrae and the vertebral arch root. 2. Ribs, because of the close position of breast cancer and ribs, infiltrative metastasis is easy to occur in this area. 3. Pelvis, also rich in blood, so cancer cells can easily colonize and multiply in the pelvis, and finally metastasize. The site of bone metastasis is not fixed, but needs to be determined by combining the site and type of disease.