Thoracolumbar Spine Anatomy and Pathology

Vertebra at the Mid Pedicle Level

Axial section through a vertebra at the mid-pedicle level

Axial section through a vertebra at the mid–pedicle level. The cancellous bone is coarse and strong. Venous vascular channels traverse the vertebral body and transgress the cortical bone posteriorly in the midline and anterolaterally on the right side. At their anterior aspect the vertebra is braced by the thick and wide anterior longitudinal ligament. By contrast, the posterior longitudinal ligament is narrow and thin and always attached to the dura. Behind the base of the transverse processes a pointed bony spike, the accessory process, lies in the trajectory along which screws typically are inserted into the pedicle. This may explain difficulties during percutaneous insertion of pedicle screws which tend to slide out of the "bulls–eye" image of the pedicle. Posteriorly, the upper sharp margin of the lamina and of the spinous process are visualized. The thecal sac is displayed at the level of the axillary outpouchings of the dura which constitute the steeply inferiorly directed offset of the root sleeves. Posteriorly the thecal sac is bounded by the sublaminar veins. These dorsal internal veins are far less voluminous than the ventral internal veins.

Updated on: 04/08/19

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