The diagnosis of atlantoaxial subluxation is mainly based on clinical symptoms, signs and x-ray performance to confirm the diagnosis. 1.Symptoms: migraine or posterior headache; vertigo, more aggravated when turning the head; accompanied by nausea, dry vomiting, head swelling. 2.Signs: (1) Restricted cervical movement, continuous rotation sign; (2) Atlantoaxial pressure pain, palpable elevation; (3) Head and neck deviation. (1) Horizontal rotation type subluxation: The lateral blocks on both sides of the atlantoaxial spine are basically symmetrical with the gap between the dentate process of the pivot (referred to as the dentate gap), and the upper and lower distances are basically equal, but the pivot spine is deviated to one side. (2) Lateral deviation type of subluxation: the gap between the right and left sides of the dentate gaps is wide and narrow, and the spinous processes of the cardinal vertebrae are deviated to the narrow side. (3) Lateral rotational subluxation: the gap between the left and right sides is wide and narrow, and the spinous processes of the cardinal vertebrae are biased to the wide side. (4) Forward-type subluxation: the anterior spacing of the cricoid teeth is increased, >2L in adults and >3L in children (mostly due to rupture of the transverse atlantoaxial ligament or excessive laxity).