The visible human anatomy of the lumbar erector spinae

Study Design. Image data of the male and female cadavers from the Visible Human Project were visualized and quantified. Objective. To clarify the anatomy of the lumbar part of the human lumbar erector spinae muscles. Summary of Background Data. Recent studies have shown discrepancies in the description of the anatomy of the lumbar part of the lumbar erector spinae. The main differences concern whether lumbar fascicles of iliocostalis lumborum exist and whether the lumbar fascicles have direct attachments to the ilium or attach via the erector spinae aponeurosis. With the Visible Human Project from the U,S. National Library of Medicine, a new powerful basis for anatomic investigation has become available. Methods. Software was produced to visualize sections oriented in any direction and with maximum resolution of the Visible Human male and female. Three-dimensional coordinates of anatomic structures in the image space could be marked in the cross-sectional images. The geometry and the physiologic cross-sectional areas of the erector spinae fascicles of lumbar origin were thus derived. Results and Conclusions. The study supports a classification of the lateral fascicles of the lumbar part of the lumbar erector spinae as part of iliocostalis lumborum. In both the male and the female, a large part of the erector spinae fibers of lumbar origin attached to the erector spinae aponeurosis. These results are of importance for biomechanical analysis of force transmission in the lumbar spine.