Disc bulge, protrusion, stenosis: what your MRI report actually means

A disc bulge means the disc extends beyond its normal border broadly, around more than a quarter of its circumference. A protrusion is a more focal push of disc material, still contained. An extrusion has broken through the outer wall. Stenosis means narrowing of the space the spinal cord or nerves travel through, and where it is narrowed matters more than the word itself. Most of these findings are common in people with no pain at all.

I am Dr Alex Freeman (chiropractor) and I practise in Victoria Park, Perth. Several times a week someone brings me an MRI report they have read on their phone in a car park, and they arrive genuinely frightened. The language is technical, it sounds structural and permanent, and nobody has sat down and translated it.

So let me translate it. Then let me explain the part almost nobody gets told, which is that a scan describes anatomy at one moment, not your future.

First, the disc itself

An intervertebral disc sits between two vertebrae. It has a tough fibrous outer ring, the annulus fibrosus, and a softer gel-like centre, the nucleus pulposus. It works as a spacer, a shock absorber and a pivot. It also loses water content steadily from our twenties onward, which is why almost every adult spine shows some change on imaging.

The words, decoded

Disc desiccation and degenerative change

The disc has lost water and signal on the scan. This is extremely common and increases with age. On its own it describes wear, not injury. That said, I do treat it as clinically meaningful rather than dismissing it entirely, because it tells me that segment has been loaded in a particular way for a long time.

Loss of disc height

The space between two vertebrae has reduced. This matters because the openings the nerves exit through, the foramina, are partly created by that disc height. Lose height and those openings get smaller.

Annular fissure or tear

A defect in the outer ring. Frequently found and frequently painless, though it can be a source of pain in some people.

Bulge

A broad-based extension of the disc beyond its normal margin, generally involving more than 25 per cent of the circumference. Technically not a herniation at all. This is the word that causes the most unnecessary alarm.

Protrusion

A focal herniation where the base against the disc is wider than the part sticking out, and the outer wall is still contained.

Extrusion

Disc material has pushed through the outer wall. The part sticking out is wider than its base. Sequestration means a fragment has separated entirely.

Worth knowing: larger extrusions often resorb over time and can produce better long-term outcomes than smaller contained protrusions. Bigger on the scan does not reliably mean worse in the long run.

Facet arthropathy and hypertrophy

The small paired joints at the back of each spinal segment have degenerative change or have enlarged. Enlarged facets take up room in the channels the nerves travel through.

Ligamentum flavum thickening

A ligament inside the canal has thickened, which also reduces available space.

Central canal stenosis

Narrowing of the main canal. In the lumbar spine this classically produces heavy, aching, tired legs with walking and standing, relieved by sitting or leaning forward.

Lateral recess and foraminal stenosis

Narrowing where an individual nerve root travels out. This is more likely to produce symptoms in one leg, following one nerve's distribution. In practice this is the group I see most often, and it is usually a combination of disc height loss, facet enlargement and bony spurring rather than one single villain.

Spondylolisthesis

One vertebra has slipped forward on the one below, graded 1 to 4. Low grade and stable is common and often manageable conservatively.

Modic changes and Schmorl's nodes

Changes in the bone next to the disc, and small disc impressions into the vertebral body. Both are common incidental findings.

The part nobody tells you

Large imaging studies of people with no back pain whatsoever find disc degeneration, bulges and protrusions at high rates, rising steadily with age. By the time people are in their fifties and sixties, a majority of pain-free spines show findings that would read as abnormal on a report.

What follows from this is important. A finding on a scan is not automatically the cause of your pain. It becomes relevant when it lines up with your symptoms and your examination. An L5/S1 protrusion on the left is interesting. An L5/S1 protrusion on the left in someone with left calf pain, a reduced ankle reflex and a positive straight leg raise on the left is a diagnosis.

But do not swing too far the other way

There is a fashion at the moment for telling people that scan findings mean nothing and that it is all just normal ageing. I think that goes too far. Degenerative change is a marker of how a segment has been loaded over years. It tells me where the wear has concentrated and where the mechanics deserve attention. Dismissing it entirely is as unhelpful as catastrophising it.

The useful position sits between the two. Your scan is real information. It is not a sentence.

Where chiropractic care actually fits

This is the part most people are surprised by, usually because their route was GP, then physiotherapy, then imaging, then a specialist referral, and chiropractic never came up.

Chiropractic care may help manage the musculoskeletal component of these presentations. Here is the reasoning I give patients, and it is deliberately mechanical rather than mystical.

When a segment degenerates, you get disc height loss and often facet enlargement or spurring encroaching on the lateral or central canal. Now, my role is not that the problem is primarily in the facet joint. But the facet joints at that level are frequently restricted, and restoring their movement takes mechanical stress off the nerve.

Even short of any structural effect, there is a second and arguably more important mechanism. Restoring movement and settling the surrounding tissue reduces the local inflammatory load. A nerve sitting in an ongoing inflammatory environment stays sensitised and stays painful. Give it a bit more room and a calmer environment, and two things tend to follow. It hurts less, and it is in a far better position to recover, because healing does not happen well in tissue that is being continuously irritated.

Alongside adjusting, that usually means loosening the surrounding tissue through soft tissue work or dry needling, targeted movement, and then strengthening the area properly once symptoms have reduced enough that you can actually do the work required.

I see good responses in people with significant lateral canal narrowing and complex disc findings. I cannot promise you a particular outcome, and I will not pretend an adjustment reverses stenosis. What I can say is that conservative care is a reasonable trial for most of these presentations before escalating, and that we measure whether it is working rather than assuming.

What would change the plan

Conservative care is not appropriate for everyone. I would refer or co-manage rather than persist if there is progressive muscle weakness, a genuine neurological deficit that is worsening, unrelenting night pain, or any sign of cauda equina compression such as saddle numbness or changes in bladder or bowel function. Those need urgent medical attention.

For everyone else, the question I care about at a progress examination is not whether your pain score moved. It is whether your strength, your range of motion and your function moved. Those are the measures that matter when anyone is weighing up injection or surgery, which is why I document them and put them in writing to your GP or specialist.

Common questions about MRI findings

Is a disc bulge serious?

Usually not on its own. A bulge is a broad extension of the disc beyond its normal margin and is a very common finding in people with no symptoms at all. It becomes clinically relevant only when it corresponds with your symptoms and examination findings.

Can a disc bulge or herniation heal?

Disc herniations commonly reduce in size over months, and larger extrusions in particular often resorb. Symptoms frequently improve well before any change on imaging, which is why repeat scanning is rarely useful for tracking progress.

Can chiropractic help spinal stenosis?

Chiropractic care may help manage the musculoskeletal symptoms associated with spinal stenosis by restoring joint movement, reducing surrounding muscle tension and improving tolerance to activity. It does not widen the bony canal. Whether it is appropriate depends on your examination findings and the severity of any neurological involvement.

Should I have surgery for a disc problem?

That is a decision for you and a surgeon, and it usually turns on progressive loss of function or neurological deficit rather than pain level alone. Most guidelines support a trial of conservative care first in the absence of red flags. Good documentation of your strength and range of motion over time makes that conversation far more informed.

Do I need a new scan before seeing a chiropractor?

No. Bring whatever imaging and reports you already have. If further imaging is warranted after examination, we refer to I-MED Radiology and go through the images with you at a report of findings appointment before care starts.

Bring your report in

If you are holding a scan report you do not understand, bring it. We are at 249B Albany Highway, Victoria Park, and we see patients from East Victoria Park, Kensington, South Perth, Como, Lathlain, Carlisle, Burswood, Rivervale and Belmont. Going through the images together and mapping them against what your body is actually doing is one of the more useful hours you can spend.

Book online or call 0493 290 505. You may also want to read about disc injuries, sciatica, chronic low back pain, and, if your findings are in the neck rather than the low back, neck pain with arm symptoms.

This article is general information and is not a substitute for individual assessment. Dr Alex Freeman is a registered chiropractor practising in Victoria Park, Western Australia.