The thoracic spinal vertebrae consist of 12 total vertebrae and are located between the cervical vertebrae (which begin at the base of the skull) and the lumbar spinal vertebrae. The third thoracic vertebra, or T3, is located a little further down the spinal column but still near the skull. Its approximate distance from the skull is about one-third of the way done the entire spine.

T3 works in conjunction with the remaining 11 segments to protect the nerves of the spine. Each vertebra is larger than the one above it, increasing in diameter as they run the length of the spine. The larger the segment, the more weight it is able to support. All vertebrae contain two stalks (pedicles) that envelope the vertebral foramen, which is nothing more than open space that the spinal cord runs through. Each vertebra contains additional open spaces called vertebral foramina that house smaller nerve roots. The thoracic spinal nerve 3 is extended from right below the third thoracic vertebra. T3 directs the flow of spinal nerve signals to and from the lungs, bronchial tubes, and chest.