Fig. 9.1. Normal cervical lordosis. Line A: drawn in an anteroposterior (AP) direction at the superior end plate of C2. Line B: drawn in an AP direction at the inferior endplate of C7. Line C: drawn in an inferior direction, perpendicular to line A. Line D: drawn in a superior direction, perpendicular to line B. Angle X, measured between lines C and D, represents cervical lordosis.
Table 9.1 Normal cervical spine curvature measurements (Fig. 9.1)
Fig. 9.2 Thoracic kyphosis. (a) Normal thoracic kyphosis. (b) Thoracic hyperkyphosis. Line A: drawn in an anteroposterior (AP) direction at the superior endplate of T4. Line B: drawn in an AP direction at the inferior end plate of T12. Line C: drawn in an inferior direction, perpendicular to line A. Line D: drawn in a superior direction, perpendicular to line B. Angle X, measured between lines C and D, represents thoracic kyphosis.
Table 9.2 Normal thoracic spine curvature measurements (Fig. 9.2)
Fig. 9.3 Normal lumbar lordosis. Line A: drawn in an anteroposterior (AP) direction at the superior endplate of L1. Line B: drawn in an AP direction at the inferior end plate of L5. Line C: drawn in an inferior direction, perpendicular to line A. Line D: drawn in a superior direction, perpendicular to line B. Angle X, measured between lines C and D, represents lumbar lordosis.
Table 9.3 Normal lumbar spine curvature measurements (Fig. 9.3)
Quantifies magnitude of spinal deformities (e.g., scoliosis).
Cobb angle ≥ 10 degrees = scoliosis.
Fig. 9.4 Cobb’s angle. Define upper and lower vertebral levels associated with curvature/deformity. Line A: drawn in an anteroposterior (AP) direction at the superior end plate of the upper vertebral level associated with curvature/deformity. Line B: drawn in an AP direction at the inferior end plate of the lower vertebral level associated with curvature/deformity. Line C: drawn in an inferior direction, perpendicular to line A. Line D: drawn in a superior direction, perpendicular to line B. Angle X, measured between lines C and D, represents Cobb’s angle.
For more information on scoliosis, see Chapter 12.
Radiograph read as if patient standing with back to you (R on R, L on L).
C7 plumb line (C7PL) = used as a reference to measure displacement of the vertebral bodies from each other and from midline (based on distance from the central sacral vertical line [CSVL]).
Coronal compensation = C7 vertebral body directly above the S1 vertebral body (despite abnormal spinal curvature).
Coronal decompensation = C7 vertebral body laterally displaced from above the S1 vertebral body.
Fig. 9.5 Coronal balance. (a) Negative coronal balance. (b) Neutral coronal balance. (c) Positive coronal balance. C7 plumb line (C7PL): vertical line drawn from the center of the C7 vertebral body. Central sacral vertical line (CSVL): vertical line drawn from the center of the S1 vertebral body.
