The sacrum is at the back of the pelvis, and its sides form the sacroiliac joint with the ilium, the sacrum forms the sacrococcygeal joint with the coccyx below, and the lumbar intervertebral disc with the lumbar vertebrae above. The sacrum is vital to the human body and is susceptible to sacral fractures in the event of trauma and causes misalignment, resulting in severe pain, swelling and restricted movement. After trauma, the sacrum is prone to develop persistent pain and other complications that affect the patient’s life, so care should be taken to protect the sacrum from trauma in general. In addition, patients with ankylosing spondylitis are also prone to destruction of the sacroiliac joints on both sides of the sacrum, causing ankylosing changes and affecting normal pelvic activities. Therefore, if there is a lesion in the sacrum, early diagnosis and early treatment are necessary.