Female back waist concave in, may be due to the following reasons: 1, may be due to the normal physiological curvature of the cause, women in the waist itself will be relative to men have more obvious physiological curvature. Female lumbar vertebrae, due to the existence of sacral curvature, will produce a very obvious S-shaped, that is, in the lumbar region has a downward concave situation, this situation is a physiological situation. 2, this situation may be due to the patient’s lumbar-sacral angle is too large, for example, the patient due to congenital hereditary factors, or anterior tilting of the pelvis and other reasons, resulting in lumbar vertebrae and sacral vertebrae intersected by the parts of the angle is too large, then it is possible to produce abnormal concavity here. 3, this situation may be due to lumbar isthmus fracture, if the patient due to congenital hereditary factors, or acquired lumbar trauma, resulting in lumbar isthmus fracture, then there is a possibility of lumbar vertebral body slippage. And once such a lesion is produced, there will also be an abnormal depression in the lumbar region.4. This condition may also be caused by scoliosis and other, bony deformities of the spine.