Slipped disc, prolapsed disc, or herniation — what's the difference?
Most people have heard the term slipped disc. Far fewer know what it actually means — or that it's not really an accurate description of what happens at all.
This blog explains what a disc injury actually is, why the terminology is confusing, what causes it, and what you can do about it.
What is an intervertebral disc?
The disc sits between each vertebra in the spine, acting as both a shock absorber and an enabler of movement. That dual function means it bears more load than almost any other structure in the body. Without discs, the spine couldn't move — which also means they're susceptible to injury.
The best way to visualise a disc is a jam doughnut:
The nucleus pulposus — the jam — is a gel-like central core, primarily made up of water. This is what gives the disc its shock absorbing properties.
The annulus fibrosus — the dough — is the outer wall, made up of layers of collagen fibres similar to those found in tendons and cartilage. It contains the nucleus and gives the disc its structural integrity.
The vertebral endplates — think of two hands holding the doughnut — bind the disc to the vertebrae above and below and allow nutrients to transfer into the disc.
A disc injury occurs when the nucleus — the jam — pushes outward through the annulus — the dough. Which is why slipped disc is such a misleading term. Nothing slips. It strains, bulges, herniates or prolapses.
What's the difference between a bulge, herniation and prolapse?
Disc injuries occur on a spectrum. At the milder end, the disc wall can strain — much like overstretching a tendon or ligament — and this often presents as what people describe as pulling a muscle in the lower back. A bulge, herniation and prolapse represent increasingly severe injuries to the same structure:
A bulge — the annulus is intact but the nucleus is pushing against it, causing an outward bulge of the disc wall.
A herniation — the annulus is compromised and the nucleus material pushes through it, though some of the outer wall remains intact.
A prolapse — more severe, where nucleus material escapes through a rupture in the annulus.
In all cases, the displaced material can irritate surrounding structures and — if it contacts a nearby nerve root — cause pain, tingling, numbness or weakness that travels into the arm or leg - known as sciatica. Pain comes from a combination of mechanical compression of the nerve and the release of inflammatory chemicals that further sensitise the area.
Something important — herniated discs are common and often painless
This is one of the most important things to understand about disc injuries. Research consistently shows that herniated discs are frequently found on MRI scans of people with no symptoms at all — no pain, no restriction, nothing. Two landmark studies — Brinjikji et al., 2015 and Nakashima, et al., 2015 — confirmed just how common asymptomatic disc changes are across all age groups.
A disc injury on a scan is not a life sentence. It is not inevitably going to cause pain. And it does not automatically mean surgery.
I know this from personal experience. I've had what I now believe to be disc related pain since my early teens — years of back pain that was never properly explained to me, and which I only came to understand through clinical training and my own research. The diagnosis that might have felt catastrophic at 13 is now something I manage well. I run, lift, swim, and look forward to playing with my son. The goal isn't to fix the disc. It's to build a body that's resilient enough to work around it.
What causes a disc herniation?
Several factors can contribute to disc injury — and it's rarely one thing in isolation.
Genetics plays a role. Some people are simply more susceptible to disc injury due to inherited variations in the structure and composition of the disc wall. If disc problems run in your family, you may be more vulnerable.
Repetitive overloading is another factor — much like any soft tissue injury, repeated stress on the disc wall without adequate recovery can cause it to fatigue and eventually fail. This is common in people whose work or sport involves sustained bending, lifting or twisting under load.
But here's the counterintuitive part — too little load is also a problem. The disc has no direct blood supply. It depends on movement and mechanical loading to draw in nutrients and expel waste. A sedentary lifestyle starves the disc of the stimulus it needs to stay healthy, gradually weakening the annulus over time.
The most striking illustration of this is astronauts. Studies have found that astronauts — who experience prolonged periods of unloading in microgravity — are significantly more likely to suffer disc herniations on return to Earth. The discs, deprived of their normal loading environment, become vulnerable. It's a powerful reminder that discs need some load to function well. The goal isn't to protect the disc from stress — it's to manage stress intelligently.
Trauma is the other common cause — typically a sudden bending and rotating movement under load that places asymmetrical stress on the disc wall in a way it can't absorb.
Of the 23 discs in the human spine, herniation is most common in the lumbar spine — the lower back — followed by the cervical spine — the neck.
Symptoms of a lumbar disc herniation
Symptoms vary depending on the severity and location of the injury:
Lower back pain — ranging from a dull ache to severe and debilitating.
A burning or stinging quality to the pain — often described as electric or gnawing.
Radiating leg pain — when the disc material irritates the sciatic nerve, pain can travel from the lower back through the buttock and into the leg. This is sciatica.
Numbness, pins and needles or weakness in the leg or foot — indicating nerve involvement.
It's also common to experience significant muscle stiffness and spasm alongside disc pain. This is largely a protective response — the muscles surrounding the injured area guard instinctively to limit movement and prevent further damage. While this is the body doing its job, prolonged muscle guarding can itself become a source of pain and restriction, often outlasting the initial disc irritation. Addressing this secondary muscle response is an important part of treatment.
If you experience sudden loss of bladder or bowel control alongside saddle area numbness — the region you'd sit on a bike — seek urgent medical attention. These can be signs of cauda equina syndrome, a rare but serious condition.
Treatment and recovery
The good news is that the vast majority of disc herniations resolve with conservative management. Surgery is rarely necessary and should be a last resort rather than a first response.
Effective conservative treatment typically involves:
Hands-on osteopathic or physical therapy treatment to reduce pain, restore movement and address the compensatory patterns that develop around an injury.
Graduated movement and rehabilitation — building load tolerance progressively rather than resting and waiting.
Load management — understanding which positions and activities aggravate symptoms and modifying them intelligently during recovery.
Posture and movement assessment — identifying the biomechanical factors that may have contributed to the injury in the first place.
Recovery is individual. Some people improve quickly. Others take longer. But with the right approach, most people with disc herniations return to full activity.
If you're based in Manchester or Didsbury and would like to discuss your symptoms, I offer initial appointments at Holland Osteopathy — book online below.