Bulging up in the middle of the back vertebrae may be caused by physiological reasons such as normal bony prominence, or it may be caused by pathological reasons such as posterior spondylolisthesis, tumors of the spine as well as soft tissues, and old injuries. 1. Normal bony prominence: there is a spinous process at the back of the vertebral body, and in thin people or in the position of arching the spine backward, the patient may appear to bulge in the middle of the spine in the back. 2. Posterior spinal deformity: common in congenital scoliosis, acquired degenerative scoliosis and other diseases, the spinal protrusion of the spine protrudes backward, which can cause the middle of the spine to bulge. 3. Spinal and soft tissue lesions: spinal tuberculosis, benign and malignant tumors of the spine and local soft tissue tumors and other diseases, the patient can appear bulging in the middle of the spine. 4. Stale injuries: patients with past traumatic injuries resulting in spinal fractures or soft tissue injuries and other stale injuries. Spinal fracture, especially serious fracture with displacement, can cause bulging in the middle of the spine if it is not properly repositioned, leading to deformity and healing. Some serious soft tissue injuries can also cause bulging in the middle of the spine after healing and scar tissue proliferation. There may also be other reasons for the bulging of the middle of the backbone, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy.