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Sagittal section through a degenerated
lower lumbar spine of a 68–year–old man who had had no history of
back pain or radiculopathy. At L5–S1 there is a complete resorption
of the intervertebral disc and a stable fusion of the cartilaginous
endplates. An almost 2 cm wide band of subchondral endplate
sclerosis borders this spontaneous fusion of the segment. In the
posterior portion of the disc, hard dark outer annular layers are
extruded into the midzone (or pedicle portion) of the root canal in
which the relatively small dorsal root ganglion snugly follows the
inferior border of the pedicle. The radicular artery is located
anterior to the ganglion and is very small. The segmental veins
which, although they are small, are not entirely collapsed. The
total resorption of the disc also entails a severe shortening of the
distance between the posterior elements as also is evident from the
axial shortening and subluxation of the facet joint. Its vertical,
apparently less loaded facet carries macroscopically normal hyaline
cartilage whereas the superior tip of the upper articular process
erodes into the inferior aspect of the pars interarticularis of L5.
There is osteoarthrosis with osteophyte formation of the tip of the
superior articular process, note also the subluxation of the L4–L5
facet joint and the obliteration of the lower portion of the
neuroforamen by disc anteriorly and the ligamentum–flavum joint
capsule posteriorly. |
©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/
