Rheumatoid Arthritis and the Cervical Spine: A Review on the Role of Surgery

Figure 2

Lateral radiographs of a patient with atlantoaxial instability. In the neutral view the AADI (arrowhead) is 1 mm and the PADI (double arrow) is 20 mm (a). In flexion the AADI increases to 7 mm and the PADI decreases to 13 mm (b). In extension the AADI and PADI reduce to their neutral measures (c).

(a)

(b)

(c)