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Midsagittal section through the
midthoracic spine of a 64–year–old female. Due to the supine
position of the cadaver there is engorgement of the deep posterior
veins. All discs show degenerative changes. The disc between T9 and
T10 is completely resorbed and the cartilaginous endplates have
fused. On the most spondylotic segments the anterior longitudinal
ligament is thicker than in the less degenerated segments. Normally
thoracic discs have a perfectly straight posterior margin. Of
surgical interest is the relationship of the laminae to the
intervening ligamentum flavum The long slender spinous processes as
well as the flat wide laminae al overlap like obliquely sloping
shingles, completely hiding the ligamentum flavum. The latter
attaches to the adjacent laminae in a consistent fashion: into the
anterior surface of the lamina above and into the upper rim of the
lamina below. Viewed from the spinal canal (anteriorly) only a
narrow band of bone is visible; the posterior wall of the spinal
canal thus is predominantly elastic–ligamentous, yet shielded by the
"hidden" lamina portion. Note that the veins behind the dura
(belonging to the posterior internal venous plexus) are invariably
located at the level of the bony lamina, not the ligamentum flavum.
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©2000 Wolfgang Rauschning, M.D., Ph.D.
Professor of Clinical Anatomy
Academic
University Hospital
Department of Orthopaedic Surgery
Uppsala, Sweden
Reproduction without permission is prohibited
http://www.akademiska.se/
