From raw to scaled human spinal cord morphometry: An original system for identifying complex anatomical patterns

Understanding the segmental anatomy of the human spinal cord remains challenging due to its interindividual variability and the lack of standardized definition of a spinal cord segment. In this human cadaveric study, we dissected 40 spinal cords, identified and measured the length, thickness and width of each segment comprised between C2 to S5. This extensive dataset enabled us to characterize the distribution and variability of the measurements, as well as to conduct ratio and correlation analyses. By converting segment length measurements into an original coordinate system, and thickness and width values into scaled data relative to easily identified anatomical features, we showed that L4 and C6 can be considered relevant landmarks of the cadaveric SC. We also divided the sample into three subgroups according to the total SC length: a short group (n = 9), an intermediate group (n = 15), and a long group (n = 16). This distinction revealed unexpected morphological features regarding the transverse dimensions, showing that variations in total SC length did not result in proportional changes in average segment thickness or width. Overall, these new morphometric findings highlight the gross morphological complexity of a generally oversimplified structure and provide additional anatomical landmarks, improving our understanding of SC cadaveric anatomy.