Function

In the lumbar spine, mainly bending and straightening as well as lateral movements are possible. Due to the special structure of the vertebral bodies and the position of the vertebral joints in relation to each other, rotational movement is virtually non-existent. A healthy lumbar spine can be bent and stretched by 70°, the lateral inclination is 25°, and the rotation capacity is approximately 2°.

As the aging process progresses, mobility decreases The smallest functional (mobile) unit of the spine 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 area colored red in each case shows the different sections of the spinal column.

From left to right:

Cervical spine and upper thoracic spine
Thoracic Spine
Lumbar spine

Side view of a motion segment

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 discs). To locally describe 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 movement segments.

The description HWK 4/5 refers to the movement segment between the 4th and 5th cervical vertebrae. In addition to its function as a static organ and as an organ of movement, the spine 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.