Figure 2

The ARA C2–C7 lordosis measurement and the C2–C7 SVA [11]. ARA C2–C7 is formed by drawing lines along the posterior body margins of C2 and C7 and measuring their angle of intersection. For the C2–C7 SVA, a vertical line originates at the posterior inferior corner of cervical vertebra C7, and the horizontal distance of the posterior superior body corner of cervical vertebra C2 is measured. Currently, this has been modified and adopted in the surgical literature as the sagittal vertical axis (SVA) of C2–C7, with a slight modification in the locations of the origins of the boney landmarks of C2 and C7 [9,13]. Both methods have excellent examiner reliability [11,16,26].