What is the thoracic spine?
The thoracic spine is the section of the spine located between the cervical spine and the lumbar spine. It begins after the seventh cervical vertebra with the first of a total of twelve thoracic vertebrae (thoracic vertebrae, Th1). In the lower region, the lumbar spine follows after the 12th thoracic vertebra (Th12).
The thoracic vertebrae are stronger compared to the cervical vertebrae and become increasingly stronger and stable towards the bottom due to the increasing body load resting on them. When viewed from the side, the upper and lower thoracic vertebrae have a larger diameter than the middle ones. The vertebral bodies are slightly higher in the front than in the back, and the anterior surface facing the chest is slightly hollowed out.
The spinous processes in the thoracic spine are long and triangular and lie on top of each other in a roof tile shape. They thus close the gaps between the vertebral arches. The two transverse processes that extend from each vertebral body point to the side in the upper thoracic vertebrae and to the side and obliquely backward in the middle and lower ones.
The thoracic spine has a natural curvature backward (thoracic kyphosis).
Rib-vertebral joints
These rib-vertebral joints allow for mobility of the rib cage, which expands and contracts with each breath. The rib-vertebral joints are additionally stabilized by numerous ligaments.
Spinal nerves of the thoracic spine
Each thoracic vertebra has basically the same structure as all other vertebrae of the spine. The vertebral holes inside the vertebral body, which form the spinal canal with the spinal cord running through it one above the other, leave the intervertebral foramen open between each two vertebrae. Through this intervertebral hole run the spinal nerves (Nervi intercostales), which emerge from the spinal cord and supply the wall of the thorax with the associated muscles, the skin and the inner skin of the chest wall.
What is the function of the thoracic spine?
The thoracic spine stabilizes the trunk. It gives the individual ribs their support and is also involved in the construction of the rib cage (thorax), which protects the internal organs.
The thoracic spine allows the upper body to tilt sideways by about 30 degrees. This sideways inclination is limited by the compression of the ribs on the respective side.
Rotation around its own axis – the rotation of the torso – is possible through the thoracic spine up to about 33 degrees.
Where is the thoracic spine located?
What problems can cause the thoracic spine?
Congenital and acquired changes can occur in the thoracic spine as well as in other sections of the spine. For example, in so-called scoliosis, the spine is curved laterally. In addition, individual vertebral bodies are twisted around their longitudinal axis.
Individual vertebrae may also be altered in shape, or their number may vary. For example, the twelfth rib may be receded and the transverse process may correspond to that of a lumbar vertebra (there are then eleven thoracic vertebrae and six lumbar vertebrae instead of the normal twelve thoracic and five lumbar vertebrae). On the other hand, a rib may still be present on the first lumbar vertebra (in which case thirteen thoracic vertebrae and only four lumbar vertebrae are present).
Sometimes individual thoracic vertebrae (or other vertebrae) are blocked in their mobility. This can be caused by muscle spasms.
Spondylarthrosis is a degenerative change of the small vertebral joints (facet joints). It occurs particularly in the lumbar region, but can also affect the thoracic spine, for example. The degenerative changes of the facet joints can cause pain. This is referred to as facet syndrome.
A herniated disc occurs less frequently in the thoracic spine than in the cervical and lumbar spine. Stress on the anterior region of each thoracic vertebra can cause protrusion of the disc, which may then lead to compression of the spinal cord and spinal nerves. The cause of the prolapse or protrusion of an intervertebral disc in the thoracic spine can be degenerative changes (wear and tear) as well as injuries.
