Anatomic study of the interrelation between lumbosacral nerve roots and their surrounding tissues.

In order to clarify the mechanism of symptom production of sciatica or intermittent claudication, the interrelation between lumbosacral nerve roots and their surrounding tissues was analyzed in 75 cadavers. The running course of nerve roots can be changed by congenital anomalies and by acquired lesions, such as compression by articular facets. Ossification of spinal ligaments may also cause nerve root compression. The space around the nervous tissue, both in the spinal canal and in the intervertebral foramen, is narrower in the male than in the female. Membranous structures, an epidural membrane, and an epiradicular sheath can be found around nerve roots. Their existence is correlated with a serpentine figure of the roots observable by selective radiculography.