Abstract
The spine is a columnar structure comprised of vertebral bones with a complex shape connected like prayer beads; various pathologies are associated with its shape and arrangement. The objective of this study was to clarify the morphological characteristics of the lumbar vertebrae. The subjects were 33 examinees aged 23-49 years （18 males and 15 females, mean age: 41.0±5.8 and 41.3±7.9 years old, respectively） with no past medical history of lumbar vertebral disease or morbid lumbar vertebral symptoms who underwent the continuous acquisition of CT. A 3-dimensional lumbar vertebral model was prepared from the CT image data acquired under the condition for bone in each subject using analysis software （MIMICS VER. 19）, and the following 3 types of measurement were performed: vertebral bone volume, minimum spinal canal area, and aspect ratio of the region with the minimum spinal canal area. The lumbar vertebral characteristics were investigated in males and females. The vertebral bone volume increased as the spinal level descended in both sexes. The minimum spinal canal area was significantly wider at L5 compared with those at higher spinal levels in the males, whereas no significant difference was noted among the lumbar vertebrae in the females. Regarding the aspect ratio of the region with the minimum spinal canal area, the transverse diameter tended to increase as the lumbar spinal level descended in the males. In the females, no significant difference was noted among L1-L5, but the ratio of the transverse diameter at L5 was significantly greater than that at higher lumbar vertebral levels. These findings clarified the presence of sex differences in the morphological characteristics, and these may influence the severity of morbid symptoms, such as spinal cord compression.
