From the case:
Coronal and sagittal balance
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A commonly used technique for assessing coronal balance and sagittal balance, on erect whole spine radiographs, involves drawing a vertical (plumb) line from the midpoint of the C7 vertebral body, down to the sacrum.
A distance of more than ~2 cm from the midline (on coronal view) and posterosuperior corner of the S1 vertebral body (on sagittal view) denotes abnormal balance respectively.