Back spine depression may be associated with the following causes: 1. There may be spine-related bony deformities, the most common being scoliosis. Scoliosis not only has abnormalities in the lateral spinal curvature, but may occur throughout the three-dimensional space. When scoliosis occurs, it may lead to a sunken back or a deformity of the thorax.2. It may be caused by an old injury related to the spine, for example, if there is an old fracture of the spine and it has not been thoroughly treated, the recovery process may leave a deformity related to the bone, leading to a local depression.3. It may also be caused by a soft tissue lesion around the spine, for example, if there is For example, if there are severe local burns or scar adhesions around the area, it is possible to pull the skin on the surface and depress it to the inside, i.e. to show a downward depression around the spine.