Axial section of the atlas through the
lateral masses and the posterior arch. The mid–portion of the
odontoid process displays articular cartilage anteriorly and also
posteriorly where it articulates with the transverse ligament.
Lateral to the dens loose areolar vascular tissue. The lateral
masses are composed of strong cancerous bone whereas the arches
contain more cortical bone. The vertebral arteries are about to
enter the transverse foramina of the atlas. They are surrounded by a
rete of veins which is continuous with the venous sinusoids which
surround the nerve roots in the root canals (periradicular venous
plexus) and with the wide sinusoids which surround the thecal sac
(epidural veins, internal vertebral venous plexus). These venous
compartments display black on cadaveric sections because they are
filled with cruor mortis. Note that these epidural veins constitute
wide vascular compartments with relatively few septa rather than a
serpiginous rete of veins. The thecal sac is oval and renders ample
space for the spinal cord which clearly displays the anterior median
fissure and the posterior median sulcus. A great number of rootlet
filaments emerging from the anterolateral and posterolateral sulcus
stepwise merge intrathecally to larger dorsal and ventral roots.
©2000 Wolfgang Rauschning, M.D., Ph.D.
Professor of Clinical Anatomy
Department of Orthopaedic Surgery
Reproduction without permission is prohibited http://www.akademiska.se/