Fig. 5

MRI and cervical lateral radiography of a patient in control group. (a) Sagittal T1 weighted fat spin echo image shows no abnormality in the atlantoaxial joint with normal range of anterior atlantodental interval. (b) In lateral cervical radiography with neutral (b) and flexion posture (c), the anterior atlantodental interval is measured less than 3 mm, which is negative for AADI method. (1.73 mm in neutral posture, 0.92 mm in flexion posture). The Swischuk line touches the spinolaminar junction of C2 (0 mm in Swischuk line method) in both neutral and flexion posture, which is also negative for Swischuk line method