Lumbar Spine Anatomy

6 Lumbar Spine Anatomy


Melissa G. Goczalk, Ankur S. Narain, Fady Y. Hijji, Philip K. Louie, Daniel D. Bohl, and Kern Singh


6.1 General Information


• Anatomy and function:


– Lordotic curvature.


– Long transverse processes for muscle attachment.


– Lacks facets for rib articulation.


– Supports weight of trunk.


– Allow flexion, extension, lateral flexion, and rotation of spine.


• Landmarks:


– L1: conus medullaris.


– L3: umbilicus.


– L4: iliac crests, aortic bifurcation.


6.2 Bony Anatomy (Fig. 6.1)


• Vertebral body:


– Cylindrically shaped and widest transversely.


• Vertebral foramen:


– Triangular spinal canal.


• Pedicles:


– Connect vertebral body to lamina.


– Directed posteriorly and located in the middle one-third of the transverse process.


• Transverse processes:


– Thin and long from L1 to L4.


– Large and cone-shaped at L5 due to iliolumbar ligament attachment to pelvic bones.


• Facet joints:


– L1–L4 facets are sagittally oriented to limit axial rotation.


– L5 facet is more coronal and resists anteroposterior movement.


– Prominent pars interarticularis.


• Lamina:


– Connect spinous process to pedicles.


• Spinous process:


– Broad and thick orientation.



6.3 Ligamentous Anatomy (Fig. 6.2)


• Anterior longitudinal ligament:


– Located on the anterior surface of vertebral bodies.


– Functions include limiting spine extension and securing intervertebral disks.


• Posterior longitudinal ligament:


– Located on the posterior surface of vertebral bodies.


– Limits spine flexion and secures intervertebral disks.


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Mar 29, 2020 | Posted by in ORTHOPEDIC | Comments Off on Lumbar Spine Anatomy

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