The varying length and relations of the osteoligamentous nerve root canals at different lumbar levels are a function of a progressively earlier exit from the dural sac by the lower lumbar nerve roots. Both the osteoligamentous nerve root canals and their terminal intervertebral canals showed significant normal narrowing at the level of the opposed intervertebral discs and facet joint capsules. This caused the normal nerve root canals to have a beaded appearance and the osteoligamentous intervertebral canals to have the appearance of long-necked gourds.
These normally narrow areas correlate well with the spondylotic neural entrapment points. Narrowing of the disc interval is an important cause of many of the interdependent degenerative changes in the lumbar spine. Hence, its reconstitution should be a major goal of spondylotic surgery.
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