A reappraisal of the anatomy of the human lumbar erector spinae
Bogduk, N.
Journal of Anatomy 131(Pt 3): 525-540
1980
ISSN/ISBN: 0021-8782 PMID: 7216917 Document Number: 158658
Dissections of the lumbar erector spinae muscle in 4 human adult cadavers revealed its morphology to be different from that traditionally described in textbooks. A revised interpretation of the morphology of this muscle is submitted. In the lumbar region, the common mass of the erector spinae is divided into 2 divisions by the erector spinae aponeurosis and its ventral continuation, the lumbar intermuscular aponeurosis. The 2 divisions are the lumbar components of longissimus and iliocostalis. Lumber fibers of the longissimus arise from the ilium and the medial surface of the lumbar intermuscular aponeurosis. They are arranged in 5 laminae which insert into the L (lumbar) 1-5 accessory processes. Lumbar fibers of the iliocostalis arise from the ilium and the lateral surface of the lumbar intermuscular aponeurosis. They are arranged in 4 laminae which insert into the distal ends of the L 1-4 transverse processes. Thoracic fibers of both longissimus and iliocostalis arise from the deep and superficial aspects of the erector spinae aponeurosis, respectively, and insert into thoracic transverse processes and ribs. The thoracic and lumbar insertions of both longissimus and iliocostalis are homologous. The description presented here is at variance with traditional descriptions of the human erector spinae but is consistent with the morphology of this muscle in laboratory animals. The laminated nature of the lumbar fibers of longissimus and iliocostalis should be taken into account in biomechanical analyses of the back muscles and the attachment of iliocostalis to lumbar vertebrae should not be neglected.