The thoracic spine encompasses the upper- and middle-back region. It joins the cervical spine and extends down about five inches past the bottom of the shoulder blades, where it connects with the lumbar spine.
There are 12 vertebra making up the thoracic spine. While the cervical spine is built for flexibility (e.g. turning the head) and lumbar spine is built for power and flexibility (e.g. lifting heavy objects, touching the toes), the thoracic spine is built for stability and does not have the same flexibility. This stability plays an important role in holding the body upright and providing protection for the vital organs in the chest.
The thoracic spine is an intricate construct of bones, muscles, spinal segments, connective tissues, nerves, and joints. Although it is solidly constructed and relatively stable, it can also be a source of pain.