The radiographic study titled, “The Posterior Cranial Vertical Line: A Novel Radiographic Marker for Classifying Global Sagittal Alignment,” [1] proposes a “novel” radiographic measurement, namely PCVL, a vertical line drawn from the back of the skull, to calculate the relative distance between it and selected points below the head of the patient. With the advent of full-body radiography, the authors were able to appreciate the global alignment of asymptomatic persons and further their understanding of the interplay between different regions of the body relative to the head. I congratulate the authors as PCVL offers a simple way to quickly assess global sagittal alignment. Other investigators also have used this fullbody scan technology to assess “head-to-toe” alignment, and as the authors have alluded to in the body of their work, came up with such concepts as cranial sagittal vertical axis (crSVA) [2]. Looking ahead, it is important to further our understanding by analyzing how each region of the spine contributes to the overall alignment. The ever important spinopelvic relationship [3] and the more recent hip-spine relationship [4] must be accounted for. Moreover, the full-body scan allows for measurement of each motion segment in the spine as, for example, lower lumbar segments contribute more to achieve lordosis than upper lumbar segments. The cumbersome task of measuring various radiographic parameters will soon be automated by artificial intelligence and machine learning technologies [5].

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