Anatomy · functional reading
Intervertebral disc
The intervertebral disc is a fibrocartilaginous structure located between two vertebral bodies. Made up of a gel-like nucleus surrounded by a fibrous ring, it transmits and distributes loads while allowing the spine to move.
Scientific basis
The disc has three parts: the nucleus (nucleus pulposus), rich in water and proteoglycans; the fibrous ring (annulus fibrosus), made of crisscrossing collagen lamellae; the cartilaginous endplates, at the interface with the vertebrae.
In adults, the disc is the largest avascular structure in the body. Its cells are nourished mainly by diffusion from the blood vessels of the vertebral bodies, through the endplates. Load variations over the course of the day change its water content and height; their exact contribution to nutrient exchange is still debated.
With age, the disc gradually dehydrates, which changes its mechanical properties.
Blue Portance / SBNFA™ reading
In SBNFA™, the disc is not regarded as a simple, isolated shock absorber. Together with the vertebrae, joints, ligaments, muscles and fascia, it takes part in a system that transmits and redistributes stress.
The focus is notably on the duration and variability of the loads it receives, not only on their value at a given moment. SBNFA™ therefore considers not only the intensity of loads, but also their duration and variability over time. This temporal dimension is part of its reading of tissue adaptability.
Contribution to the analysis of sitting
In the seated position, the orientation of the pelvis changes the lumbar curve and therefore the distribution of loads on the discs. A seat can be analyzed according to the lumbopelvic organization it encourages and according to whether it allows that organization to vary over time.
Not to be confused with
Intervertebral disc disease, an alteration of the disc; herniated disc, a localized displacement of the nucleus; intradiscal pressure, a quantity measured inside the disc.
Related terms
Intervertebral disc disease · Herniated disc · Intradiscal pressure
Sources and scope
- Urban, Smith and Fairbank (2004): nutrition of the intervertebral disc (Spine)
- Adams and Roughley (2006): what is intervertebral disc degeneration, and what causes it?
- Fardon et al. (2014): lumbar disc nomenclature, version 2.0
The anatomy and physiology of the disc are established. Disc nutrition and the disc's role in pain are the subject of ongoing research.
