The hazards of short and long legs are mainly in the following aspects: 1, can cause pelvic tilt, serious strain on the muscles around the pelvis, and pain symptoms, can also cause lumbar scoliosis, the patient will have lumbar pain and lumbar spine activity limitation, the longer the history of the disease will also cause lumbar disc herniation, and secondary lumbar spinal stenosis, the nerve will cause long-term compression, which will lead to lower limb muscle atrophy, weakness, and sensory loss. 2. Long and short legs are also harmful to the joints of the lower limbs, such as hip joints, knee joints and ankle joints, which can lead to serious degenerative changes in the above joints, unbalanced joint loading, and gradually aggravate the damage to the joint cartilage, resulting in joint pain, limited joint movement, and even deformity of the joints. Therefore, long and short legs have serious harm to human body and should be treated early to correct long and short legs and prevent serious sequelae.