In Depth: Vertebrae and Nerves
The 12 vertebrae of the thoracic spine represent the middle of the spinal column, the bony tower that provides support for standing and sitting as well as houses the spinal cord. The spinal cord is the fibrous band of nerves that extends from the brain down the back. The brain communicates with the body via the spinal cord and its branches. The thoracic spine curves away from the body at its top but returns inward before it ends.
The vertebrae of the thoracic spine are numbered T1 through T12. The “T” stands for “thoracic.” T1 is located just above the collarbone, and T12 is located in the small of the back where it curves in.
The thoracic vertebrae vary in size. The ones near the cervical spine are smaller, and those near the lumbar spine are bigger. The lowest vertebra, T12, is the largest in the thoracic spine.
Each thoracic vertebra has an indent at the top and bottom of its body, the largest part of the vertebra. The 12 pairs of rib bones extend from these indents, or facets. Most of these curved flat ribs wrap around the body and connect to the chest bone, or sternum, via the coastal cartilage. The bottom three sets of ribs hang freely and do not connect in front.
Between each vertebra is a squishy pad that protects the vertebrae from grinding against one another and creates a small joint that makes movement possible. These pads are called intervertebral discs, and they absorb shocks and distribute pressure on each vertebra. These discs can become damaged through injury or deterioration, and this often causes long-term pain.
Although the cervical vertebrae of the neck are more commonly injured, thoracic vertebrae can be fractured due to falls, car accidents, and blunt force trauma. Vertebral fracture can lead to paralysis and other long-term disabilities.
Thoracic vertebrae are most commonly injured in car accidents when the upper body is thrown forward, but the seatbelt restrains the lower body. These injuries were more frequent with lap-only belts, but modern seatbelts have decreased these injuries.