Axial section through C5–C6 of a normal
cervical spine that was frozen in situ in moderate flexion. The
obliquity of the articular facets induces an antero–listhesis of C5
on C6 that widens the sagittal diameter of the spinal canal and the
"neuroforamina". The thecal sac, root sleeves and vertebral arteries
are surrounded by a large sinusoid venous compartment. The almost
round thecal sac is bordered posteriorly by the interlaminar
ligamentum flavum that is stretched and hence thinner than normal.
Anteriorly the dura is firmly affixed to the posterior longitudinal
ligament which "fans out" as it approaches the endplates and the
disc, firmly affixing the dura anteriorly at each disc level.
Flexion causes the spinal cord to move anteriorly in the thecal sac.
The distraction of the articular processes markedly widens the
intervertebral foramina, which are long osseoligamentous tunnels
that rather should be referred to as root canals. Variable root
tension in various postures and the denticulate ligament control the
movements of the spinal cord. Note the anterior and posterior spinal
arteries and veins on the surface of the spinal cord.
©2000 Wolfgang Rauschning, M.D., Ph.D.
Professor of Clinical Anatomy
Department of Orthopaedic Surgery
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