Function of the thoracic spine
The range of motion of the thoracic spine is small, since the attachment of the ribs and the tile-like arrangement of the spinous processes do not allow a large range of motion. The most important function of the thoracic spine is the rotation of the trunk. Rotational movements of the trunk are almost without exception carried out in the lower thoracic spine.
In addition, the movements of the costal vertebral joints are important for inhalation and exhalation. Due to a different joint type, the upper pairs of ribs of the 2nd -5th rib (swivel joint) perform a different rib movement (forward lifting of the ribs) than the pairs of ribs of the 6th -9th rib (sliding joint; lateral lifting of the ribs). Overall, this increases the volume of the ribcage during inhalation.
Diseases that restrict this mobility (e.g. ankylosing spondylitis) lead to disturbance of the respiratory movements (respiratory excursion). The smallest functional (mobile) unit of the spinal column is the mobile segment. A mobile segment is the unit between two adjacent vertebral bodies connected by two vertebral joints, as well as the intervertebral disc between the vertebral bodies and all muscular, ligamentous and nerve structures located in this area.
The red colored area shows the different sections of the spinal column. From left to right:
- Cervical spine and upper thoracic spine
- Thoracic spine
- Lumbar spine
- Vertebral body
- Intervertebral disc
- Spinal cord nerve root
- Intervertebral hole (Neuro foramen)
- Vertebral joint
- Spinal process of the vertebra (palpable on the back as the rear end of the vertebra)
Isolated disorders are often located in a single movement segment (e.g. blockages, herniated disc of BWS). For the local description of a spinal disease, the individual vertebral bodies are counted, e.g. HWK 5 for the 5th cervical vertebral body, BWK 9 for the 9th thoracic vertebral body, LWK 3 for the 3rd lumbar vertebral body, etc.
The same applies to the intervertebral discs and the mobile segments. The description BWK 7/8 refers to the mobile segment between the 7th and 8th thoracic vertebral bodies. In addition to its function as a static organ and as an organ of movement, the spinal column has another important function as a protective and management organ for the spinal cord. In principle, the spinal cord represents the extension of the brain and is therefore also assigned to the central nervous system. – Transverse process
- Outgoing nerve
- Vertebral body
- Spinous process
- Spinal cord
Diseases of the thoracic spine
Diseases of the thoracic spine are less common than those of the cervical and lumbar spine, especially with regard to the frequent wear-related clinical pictures (e.g. facet syndrome, herniated disc, spinal canal stenosis, etc.). Nevertheless, dorsalgia, as back pain in the thoracic spine is unspecifically called, occurs frequently. In young people, this often conceals blockages of the intervertebral joints or the costal vertebral joints.
A blockage is the temporary, reversible reduced mobility of a joint that causes pain due to the “entangled” malposition and capsule tension of the joint. Muscle tension of any kind can occur independently, for example due to incorrect loading, or it can appear as an accompanying disease. A slipped disc of the thoracic spine is very rare (<1% of all slipped discs).
In older people, pain in the thoracic spine is often caused by a reduction in bone mass (osteoporosis). This in itself painful disease can become even more accentuated in the thoracic spine if a vertebral body fracture has occurred due to the greatly reduced load-bearing capacity of the vertebral bodies. Modern minimally invasive therapeutic procedures, such as vertebroplasty and kyphoplasty, are increasingly used to treat such fractures. Accident-related (traumatic) fractures of the vertebral bodies occur more frequently in the area of the transition from the thoracic to the lumbar spine. This is mainly caused by the reversal of the curvature from thoracic kyphosis to lumbar lordosis.
