A herniated disc occurs when the intervertebral disc's outer fibers (the annulus) are damaged and the soft inner material of the nucleus pulposus ruptures out of its normal space. If the annulus tears near the spinal canal, the nucleus pulposus material can push into the spinal canal. In the thoracic area, there is very little extra space around the spinal cord. Luckily, herniated discs in the thoracic area are not nearly as common as in the lumbar spine.
The purpose of this information is to help you understand some simple facts.