Cervical lateral radiograph
b Detail of 36-inch lateral radiograph showing measurements
a. Occiput-C2 sagittal Cobb angle,
b. Occiput-C7 sagittal Cobb angle,
d. C2-C7 sagittal Cobb angle,
e. T1 tilt.
Horizontal solid white line: C1-C7 Sagittal Vertical Axis - distance between plumb line dropped from anterior tubercle of C1 and posterior superior corner of C7; Horizontal white dotted line: C2-C7 Sagittal Vertical Axis—distance between plumb line dropped from centroid of C2 and posterior superior corner of C7; White dashed line: Center of Gravity-C7 Sagittal Vertical Axis—distance between plumb line dropped from anterior margin of external auditory meatus and posterior superior corner of C7.
The K-line is a straight line connecting the midpoints of the cervical spinal canal at C2 and C7 on a neutral cervical lateral radiograph.
The maximum occupying ratio of the cervical ossification of the posterior longitudinal ligament (OPLL) is calculated from a cervical sagittal computed tomography.