A View Inside the Lumbar Erector Spinae: the Visible Human Project
The portion of the lumbar erector spinae that delivers force over the lumbar spine consists of the iliocostalis lumborum and logissimus thoracis. Recent studies have shown discrepancies in the precise anatomical characteristics of the lumbar portion of the erector spinae, leading researchers to speculate on whether lumbar fascicles of iliocostalis lumborum exist, and whether such fascicles have direct attachments to the ilium.
This study relied on cadaveric image data from the Visible Human Project. Shortly after death, a male and female were frozen and fixated in gelatin. The cadavers were then dissected at intervals of one millimeter or less, using a process called cryosectioning. Images of each section were taken in 24-bit true color. The authors of this study used the lower trunk of both subjects to clarify the anatomy of the lumbar portion of the human lumbar erector spinae muscles. Software was produced to visualize cadaver sections oriented in any direction and with maximum resolution. Three-dimensional coordinates of anatomic structures in the image space could be marked, deriving geometry and physiologic cross-sectional areas of the erector spinae fascicles of lumbar origin.
Results: In both male and female specimens, a large portion of the erector spinae fibers of lumbar origin attached to the erector spinae aponeurosis, supporting classification of the lateral fascicles of the lumbar portion of the lumbar erector spinae as part of the iliocostalis lumborum.
The authors note that accurate anatomic description of the lumbar erector spinae is vital to understanding injury mechanisms of the lumbar spine. They add that their findings are important for biomechanical analysis of force transmission in the lumbar spine.
Note: The specimens from the Visible Human Project can be viewed on line at the National Library of Medicine’s website: www.nlm.nih.gov/research/visible/visible_human.html.
Daggfeldt K, Huang Q-M, Thorstensson A. The visible human anatomy of the lumbar erector spinae. Spine 2000:25(21), pp2719-2725.
