Fig. 2. Radiologic measurements. Cervical alignment (CA) and segmental angle (SA) was measured in neutral position using Cobb method (A). Upper segmental range of motion (USROM, U2–1) and lower segmental range of motion (LSROM, L2–1) was measured in both flexion and extension position (B and C). Segmental height (SA), upper segmental disc height (UDH), and lower segmental disc height (LDH) was measured along the line passing through the center of the vertebral bodies (D). For formulas and study time point, see Table 1.