The spine has a double S-shape that cushions stress and shocks. Elastic intervertebral discs are located between the vertebral bodies and act as shock absorbers. Spinal disorders can lead to symptoms such as back pain or a herniated disc.
Structure of the Spine
The spine is structured as follows:
- 7 cervical vertebrae of the cervical spine
- 12 thoracic vertebrae of the thoracic spine
- 5 lumbar vertebrae (lumbar vertebrae) of the lumbar spine (LWS)
- 5 fused sacral vertebrae of the sacrum (Os sacrum)
- 4–5 rudimentary coccygeal vertebrae of the coccyx (os coccygis)
The upper part of the spine (cervical, thoracic, and lumbar spine) is mobile.
The Individual Vertebrae
The components of a vertebra are
- Vertebral body (Corpus vertebrae)
- Vertebral arch (Arcus vertebrae)
- Spinous process (Processus spinosus)
- two transverse processes (Processi transversi, Processi costales)
- four articular processes (Processi articulares)
The first and second cervical vertebrae are exceptions.
The vertebral arch encloses the vertebral body in a horseshoe shape, forming—together with the arches of other vertebrae—the so-called vertebral canal (Canalis vertebralis). The spinal cord and nerve roots are protected within this canal. The back muscles attach to the two transverse processes and the dome process. Find your specialist here with ease.
The Intervertebral Discs
The 23 intervertebral discs (also called discus intervertebralis) in the human spine are elastic connectors between pairs of vertebral bodies (exceptions: the first and second cervical vertebrae, and the sacral and coccygeal vertebrae).
An intervertebral disc consists of a relatively firm outer fibrous ring and a viscous gel-like nucleus located inside (composed of 80 to 85 percent water). The flexibility of the intervertebral discs, which results from their structure, allows the spine to move and absorbs shocks from running, jumping, etc. (cushioning function).
Since the intervertebral discs lose fluid and become thinner under stress, a person’s height decreases by approximately 1.5 to 2 cm over the course of the day. At night, when the spine is relieved of stress, the discs reabsorb water and nutrients, causing a person to be taller again in the morning.
Signs of wear and tear and improper loading can lead to the destruction of the annulus fibrosus, which can result in a herniated disc (protrusion of disc material).
Illustration of the intervertebral discs and a herniated disc © Sebastian Kaulitzki / Fotolia
Spinal Disorders and Injuries
The spine can be affected by various conditions. These include
- degenerative changes (e.g., herniated disc)
- inflammatory rheumatic diseases (e.g., ankylosing spondylitis)
- instabilities, including spondylolisthesis (slipping of the vertebrae)
- Deformities (e.g., scoliosis, a lateral curvature of the spine)
- Growth disorders (e.g., Scheuermann’s disease)
- Tumors (chordomas)
If the spine is severely injured (e.g., in an accident) and the spinal cord is damaged, paraplegia results. In such a case, it makes perfect sense to see an appropriate specialist.
Conclusion
The spine is a central support structure of the human body and enables upright posture, while simultaneously stabilizing the back and maintaining its mobility. Anatomically, the spine consists of numerous vertebrae, whose vertebral bodies are connected by intervertebral discs and act as natural shock absorbers during any impact. The spinal cord and important spinal nerves run through the spinal canal, while the vertebral arches, spinous processes, and vertebral bodies are bony structures that, together with ligaments and the back muscles, ensure stability.
The cervical, thoracic, and lumbar spine, together with the sacrum, coccyx, and sacrum, form a curvature in the shape of the characteristic double S-curve, which distributes stress evenly. Between the vertebral bodies lies each intervertebral disc with its gel-like nucleus, which reacts elastically to stress and thereby maintains the mobility of the spine. If wear and tear, scoliosis, or a herniated disc occurs, back pain and other symptoms may develop, which is why such conditions are frequently treated in orthopedics. In addition, the joints, muscles, and cervical vertebrae surrounding the first vertebra (the atlas) connect the rib cage, the ribs, the pelvis, and the lumbar vertebrae, while some sections are fused together, forming a particularly stable and supportive spine.
FAQ
What is the spine and what is its function?
The spine forms the backbone of the human body and is a central axis of the skeleton. It serves as a support for the trunk, protects the spinal cord, and enables movement of the back. Thanks to its structure of vertebrae and intervertebral discs, the spine remains both stable and flexible.
How is the spine structured?
The spine consists of several sections. These include the cervical spine, thoracic spine, and lumbar spine, as well as the sacrum and coccyx. Each section of the spine consists of several vertebral bodies connected by intervertebral discs and ligaments.
What role do intervertebral discs play?
Intervertebral discs are located between the vertebral bodies and act as elastic shock absorbers. They consist of a fibrous ring and a gel-like center, known as the nucleus pulposus. This structure ensures the spine’s mobility and distributes stress during movement.
What conditions commonly affect the spine?
Common conditions affecting the spine include herniated discs, scoliosis, and degenerative disc disease. These conditions can cause back pain and limit mobility. Such conditions are frequently treated in orthopedics.
Why is the double-S shape of the spine important?
The double-S shape of the spine is created by natural curves such as lordosis and kyphosis. These curves help distribute stress evenly. As a result, the spine can better absorb shocks and stabilize the body while walking upright.
