Extraforaminal ligament attachments of human lumbar nerves.
METHODS
An anatomic study of the extraforaminal attachments of the lumbar spinal nerves was performed using human lumbar spinal columns.


OBJECTIVE
To identify and describe the existence of ligamentous structures at each lumbar level that attach lumbar spinal nerves to structures at the level of the extraforaminal region.


BACKGROUND
During the last 120 years, several mechanisms to protect the spinal nerve against traction have been described. All these structures involved are located in the spinal canal, proximal to the intervertebral foramen.


METHODS
Five embalmed human lumbar spines (T12-S1) were used. Bilaterally, the extraforaminal region was dissected to describe and measure anatomic structures and their relationships. Histology was performed with staining on the sites of attachment and along the ligament.


RESULTS
The levels T12-L2 show bilaterally 2 ligaments, a superior extraforaminal ligament and an inferior extraforaminal ligament. The superior extraforaminal ligament emerges from the joint capsule of the facet joints and inserts in both, the intervertebral disc and the ventral crista of the intervertebral foramen, passing the spinal nerve laterally. In one specimen on level L2-L3, the superior extraforaminal ligament is not attached to the spinal nerve. The inferior extraforaminal ligament emerges from the intervertebral disc, passing the nerve medially and attaching the spinal nerve. At the levels L2-L5, the inferior extraforaminal ligaments are only attached to the intervertebral disc, not to the joint capsule. Histologically, the ligaments consisted of mainly collagenous structures.


CONCLUSIONS
Ligamentous connections exist between lumbar extraforaminal spinal nerves and nearby structures.
Kraan
G A
GA
Department of Biomedical Physics and Technology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands. orthop@vumc.nl
Delwel
E J
EJ
Hoogland
P V J M
PV
van der Veen
M R
MR
Wuisman
P I J M
PI
Stoeckart
R
R
Kleinrensink
G J
GJ
Snijders
C J
CJ
D000369:Aged, 80 and over; D002102:Cadaver; D004388:Dura Mater / Q000033:anatomy & histology*; D006801:Humans; D008023:Ligaments, Articular / Q000033:anatomy & histology*; D008159:Lumbar Vertebrae / Q000294:innervation*; D008161:Lumbosacral Region; D013126:Spinal Nerve Roots / Q000033:anatomy & histology*; D021801:Zygapophyseal Joint / Q000294:innervation