31/12/2025
https://www.facebook.com/share/p/1Auy2VGUcf/
A bulged or herniated disc hurts so much because displaced disc material irritates and compresses very sensitive nerve roots, and common postures like slumped sitting actually increase the pressure on those discs instead of relieving it.
What a disc actually does
Each intervertebral disc sits between two vertebrae and has a gel‑like nucleus pulposus in the centre and a fibrous annulus around it, acting as a shock‑absorbing cushion and spacer for the nerve roots.
When the annulus weakens or tears, the nucleus can bulge or herniate backwards, where the posterior longitudinal ligament is thinner and the nerve roots are close, making compression and inflammation likely.
Why pain radiates down the leg or arm
The disc itself has limited pain receptors; the severe pain comes when bulged material contacts or compresses a spinal nerve root, causing radicular pain that follows that nerve’s pathway (for example, down the leg as “sciatica”).
Nerve‑root compression can also cause numbness, tingling, and weakness in the corresponding dermatome and myotome, not just local back pain.
Sitting, standing, lying: load on your discs
Classic intradiscal pressure studies show that unsupported sitting loads the lumbar discs roughly 20–40% more than relaxed upright standing, and slumped sitting increases it even further.
Lying down significantly reduces disc pressure but does not drop it to zero; spinal ligaments and muscles still maintain about 10–20% of standing load, so symptoms may improve but not fully disappear.
Why simply “getting off your feet” is not enough
Because flexed postures increase intradiscal pressure, many people actually feel worse in prolonged sitting, bending, or driving than in gentle walking or supported standing.
If the disc and nerve are already inflamed, even small additional loads or awkward positions can keep the nerve irritated, so pain feels inescapable whether sitting, standing, or lying.
Decompression and long‑term disc health
Short‑term decompression strategies include positional unloading (lying flat with legs elevated), traction‑type techniques, and exercises that gently open the spaces where nerve roots exit.
Over time, regular movement, avoiding long static postures, weight management, better lifting mechanics, and good trunk control help maintain disc hydration and reduce degenerative changes.
