Reliability of the L3 Transverse Process as a Landmark for Lumbar Spine Enumeration Across Different Vertebral Segmentation Patterns: A Retrospective CT Study

Background/Objectives: Vertebral numbering on limited lumbosacral imaging is difficult when the thoracic or lumbar count varies. The L3 transverse process has been proposed as a landmark because it is often the longest, but this has not been tested across segmentation patterns. This study assessed whether L3 as the level bearing the longest transverse process is independent of thoracic and lumbar vertebral count on whole-spine CT.