Table 2.

Common measurements obtained from standard cervical spine plain radiographs. These measurements are not always performed unless an important sagittal deformity of the spine is deemed responsible for the myelopathy. Some variation exists amongst different authors or according to the position of the patient at the time the radiograph was taken [28].

Radiologic Measures	Normal Values	Explanation
Cobb C1–7/C2–7 angle	18 degrees +/− 12 degrees	The angle between the line parallel to the inferior endplate of C1/C2 to parallel to the inferior endplate of C7.
C7 slope	Normal values vary according to the individual cervical lordosis	Angle between a horizontal line and the superior endplate of C7
T1 slope	Normal values vary according to the individual cervical lordosis	Angle between horizontal plane at T1 endplate
Cervical sagittal vertical alignment (SVA)	15 mm +/− 11 mm	The distance from the posterior, superior corner of C7 to the plumbline from the centroid of C2
Cervical tilt	43 degrees +/− 6 degrees	The angle between two lines, both originating from the centre of the T1 upper end plate; one is vertical to the T1 upper end plate and the other passes through the tip of the dens