German term (edited): Lot vom Zentrum C7

https://radiopaedia.org/articles/sagittal-balance-c7-plumb-l...
One of the simplest and widely used methods is performed on lateral standing full-length films and requires a vertical line (plumb line) drawn from the middle of the body of the C7 vertebral body. This line should pass through the superior endplate of S1, or more precisely within ~2 cm (some use 1.7 cm) of the posterosuperior corner of the S1 vertebral body

So the sagittal C7 plumb line falls x cm in front of S1.

A value of 6 cm indicates sagittal plane imbalance.
http://www.orthobullets.com/spine/2041/adult-spinal-deformit...

https://radiopaedia.org/articles/coronal-balance
To assess coronal balance, a vertical (plumb) line is drawn downwards from the mid-point of the C7 vertebral body (exactly in the same way as for the assessment of sagittal balance... The horizontal distance between this plumb line and the midline of the sacrum or central sacral vertical line is measured

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Note added at 5 hrs (2017-10-12 11:19:45 GMT)
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Since Anne has pointed it out, I think a rewrite is indeed necessary.
Example: The sagittal offset of the C7 plumb line is about 6 cm anterior to the superior endplate of S1. The coronal offset...

Body Planes: https://www.spineuniverse.com/anatomy/anatomical-planes-body