In continuation with spinal canal of cervical spine, spinal canal in thoracic and lumbar spine consists of vertebral body, intervertebral disc, posterior longitudinal ligament anteriorly, pedicles, medial aspect of facet joints on either side laterally and ligamentum flavum & laminae posteriorly.

Injury can cause compromise of the spinal canal and the most common cause is posterior bony retropulsion from a burst fracture of the vertebral body.

Dislocations and fracture dislocations of vertebrae leading to translation between adjacent vertebrae can also cause reduction in canal space. Anterirorly displaced fractures of posterior elements [laminae] can also compromise the canal space.

Postraumatic hematoma formation, disc herniations are other causes of compression following injury.

Lumbar canal stenosis is frequent non traumatic cause of reduction of canal space and neural compromise.

Conus medularis is most distal aspect of the spinal cord and its location varies between T12 and L3. Spinal canal dimensions relative to  spinal cord dimensions are smallest in the T2-T10 region and for this reason the neurologic injury is more commmon after trauma in this region.

Complete spinal cord injury is six times more common than incomplete injury with high-energy trauma to the midthoracic spine .

In addition to smaller canal space,  another factor which is responsible for susceptibility is the lesser vascular supply to the spinal cord. The region between T2 and T10  derives its proximal blood supply from antegrade vessels in the upper thoracic spine and distally from retrograde flow from the artery of Adamkiewicz. [Read more...]