September 29, 2005 was a normal day, but for 10-year-old Tingting, it was an unusual day. She fell off the double bar while playing at school and landed on her head and shoulder, which caused pain in her left shoulder and prevented her from moving. Tingting was then taken to a local hospital, where she was diagnosed with a left clavicle fracture after taking an X-ray and was hospitalized and scheduled for surgery. The fracture healed, but Tingting kept feeling pain and discomfort in her neck, and she was stiff and unable to move. The family began to wonder if Tingting had an intracranial injury. A CT head examination at the local hospital revealed no abnormalities, but the parents were unsure and found a doctor at a small clinic. After the clinic doctor saw her, he gave Tingting a few neck massage, and the neck pain was slightly relieved, but the neck pain symptoms still did not improve. The pain always bothered Tingting’s family, and her father took Tingting to all the major hospitals in Inner Mongolia, but nothing was found, which also affected Tingting’s study. When a relative in Beijing found out about this, he learned through the Internet that the orthopedic department of China-Japan Friendship Hospital was very experienced in treating upper cervical spine diseases, so he called Tingting’s father. After carefully inquiring about Tingting’s medical history, he immediately realized the seriousness of the problem and immediately took pictures of Tingting, the results of which surprised Tingting’s father. Tingting had a rare atlantoaxial subluxation, and the severity of the subluxation was surprising, as a slight negligence could be life-threatening. So how did Tingting’s rare disease come about? Most severe pediatric atlantoaxial instability like Tingting’s is caused by cervical spine injuries. Unlike adults, the pediatric cervical fulcrum is located at the C2-3 and C3-4 segments, which are closer to the atlantoaxial spine than the adult fulcrum; at the same time, the pediatric head is relatively large and the neck muscles are relatively weak, the articular processes are more horizontal, and the intervertebral joints are underdeveloped, making this structure the anatomical basis for pediatric cervical spine injuries in the upper cervical segment. It was Ting Ting’s accidental fall from the double bar that caused the atlantoaxial dislocation. Since the clavicle fracture concealed the atlantoaxial dislocation, which was actually more serious, it was not diagnosed and treated in a timely manner, causing the dislocation to gradually worsen. It was a close call at the moment. After a clear diagnosis of her condition, a thorough surgical plan was developed and performed for little Tingting after careful study. The surgery was very successful and Tingting was discharged a week later with her headache completely gone and a big smile on her face. However, it should be emphasized that although severe pediatric atlantoaxial instability is not very common in clinical practice, it is difficult to treat clinically. Due to the physiological anatomical peculiarities of pediatric patients, it can often cause sudden high cervical marrow injury resulting in death or paralysis, or delayed atlantoaxial dislocation, losing the best time for treatment and increasing the difficulty of treatment, which should be taken seriously by parents of children.