Disc Bulge vs Herniation: What Those MRI Words Mean

Disc Bulge vs Herniation (Protrusion, Extrusion, Sequestration): What Your MRI Report Means in Plain English

If your MRI report says disc bulge, protrusion, extrusion, sequestration, or encroachment, it can feel like your back (or neck) is falling apart.

Here’s the truth: most MRI words are shape words, not doom words. It may very well be the MRI findings aren’t even the culprit. There is hope.  Keep reading.

If you also saw DDD, read this next (it fits perfectly with this page):
What Does DDD Mean on an MRI Report?

What is a disc?

A spinal disc sits between two spinal bones (vertebrae). Think of it like a tough jelly donut:

• Annulus (outer ring): the tough “tire” that holds everything together
• Nucleus (center): the softer “gel” that helps absorb shock

Key idea: When the annulus is healthy, it keeps the nucleus where it belongs.

A normal disc has a tough outer ring (annulus) and a softer center (nucleus)

What is a disc bulge?

A bulge usually means the disc is pushing outward, but the outer ring is still mostly holding.

Basic bulge

• the annulus gets stretched
• the disc edge bows out a bit

Broad-based bulge

• the same thing happens, but over a bigger section of the disc

A bulging disc happens when the nucleus pushes the disc outward toward peripheral nerves

Why bulges and herniations often drift to the side (and why that’s where trouble happens)

There’s a strong band inside the spinal canal called the posterior longitudinal ligament (PLL). It runs up and down behind the discs.

• The PLL tends to “block” a herniation from moving straight back (good news—this is closer to the spinal cord).
• You may see the term posterolateral disc herniation.

Posterolateral means:

• Postero = toward the back
• Lateral = toward the side

And what sits off to the side? The nerve “tunnel” where nerves exit the spine:

• IVF = intervertebral foramen (think: the nerve tunnel)

So when a bulge or herniation shifts sideways, that’s where encroachment can happen.

Protrusion vs extrusion vs sequestration (easy version)

These are all types of disc herniation. The main difference is what happened to the annulus (the outer ring).

Protrusion

• the annulus is weak and stretched
• it may have tiny tears, but it’s still mostly containing the nucleus
• the disc pushes out in one main spot

Extrusion

• the annulus has a clear tear
• some nucleus material pushes through that tear
• this can irritate nearby tissue strongly

Sequestration

• a piece of disc material breaks off
• that piece can move slightly away from the disc

These terms describe how much the outer ring (annulus) has been stressed or torn.

“My leg hurts but the MRI says no nerve contact.”

This is one of the most frustrating situations.

Why the mismatch happens (one big reason)

Most MRIs are done lying down. But many people feel worse when they are:

• sitting
• standing
• bending
• lifting

When you lie down, pressure changes. The disc and nearby tissues can shift by tiny amounts. And with nerve pain, tiny amounts matter.

Your symptoms still count.

Reassurance: nerve pain can be a “game of millimeters”

A few millimeters of space can be the difference between “I can’t sit” and “I’m okay.” Improvement can come from:

• swelling calming down
• inflammatory chemicals settling down
• better movement and better loading
• the disc shrinking or resorbing over time
• a spine that moves better and unloads irritated tissue

The wild part: the “worst” herniations often have the best prognosis

This one surprises people: disc extrusions and sequestrations can look dramatic, but they often shrink more than simple bulges over time.

Bottom line: A dramatic-looking MRI finding does not automatically mean a bad outcome.

Why the pain can be severe: chemistry (not just pressure)

People think nerve pain only comes from “pinching.” But nerve pain can also come from inflammation chemistry around the nerve.

• strong leg pain with “minimal contact” can happen
• contact on the image with very little pain can also happen

Inflammation + nerve sensitivity can be the main driver.

Where low-level laser therapy fits (Theralase-style laser care)

When the nerve is angry, anything that safely reduces inflammation and pain signaling can help the whole case move forward.

Clinical translation: Laser helps cool down the “chemical fire,” and you can often move better, sleep better, and progress faster.

Chiropractic spinal adjustments and radiating pain

Chiropractic care can be effective, even when pain is traveling down an arm or leg—when the care plan matches the person.

Myths

Myth 1: “If the MRI shows a herniation, I’m broken.”

No. Many people have disc findings and do fine—especially with age.

Myth 2: “If the MRI says no contact, my leg/arm pain isn’t real.”

False. Lying-down imaging can miss what happens when you sit or stand.

Myth 3: “If it says contact, I must have symptoms.”

False. Some people have contact on imaging and feel okay.

Myth 4: “Extrusion/sequestration means surgery.”

Not automatically. Many cases improve without surgery.

When to take it seriously right away (red flags)

Most cases are not emergencies, but get urgent medical assessment if you have:

• bowel or bladder control changes
• numbness in the saddle area (groin/perineum)
• rapidly worsening weakness (like foot drop)
• fever/chills with severe back pain
• major trauma with new severe symptoms

What to do next (simple plan)

1. Match the MRI to your symptoms and physical exam with an expert.  The MRI report isn’t the whole story.
2. Calm the nerve down (inflammation + sensitivity) with laser and restore motion with chiropractic.
3. Build tolerance back (walking, graded movement, strength when ready). We will help you with an exercise program.
4. If you’re in Ottawa/Nepean and want a clear plan, book an evaluation and we’ll map your symptoms to the findings. Here is what you can expect on your first visit. 

FAQ

What’s the difference between a disc bulge and a herniation?

A bulge is the disc edge pushing outward while the outer ring is still mostly holding. A herniation usually means the outer ring has weakened or torn, so inner material can push out more.

Does a bulging disc always cause pain?

No. Many bulges are found in people who feel fine. Your symptoms and exam matter more than the word alone.

Is a protrusion “better” than an extrusion?

Not always. Both can be painful. The good news is that many disc herniations can improve over time.

What does “sequestration” mean?

It means a small piece of disc material has broken off from the main disc.

Why does my MRI say “no nerve contact” if I have sciatica?

Because most MRIs are done lying down, and symptoms often happen sitting or standing. Also, inflammation around the nerve can cause strong pain even without obvious contact.

What does “encroachment” mean on an MRI report?

It usually means something is taking up space near a nerve pathway (like the nerve tunnel). It does not automatically mean permanent damage.

When should I seek urgent medical care?

If you have bowel/bladder changes, saddle numbness, rapidly worsening weakness, fever with severe back pain, or major trauma with new severe symptoms.

References (research links)

1. Brinjikji W, Luetmer PH, Comstock B, et al. Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. AJNR (2015).
   PubMed |
   Full text (PDF)
2. Jensen MC, Brant-Zawadzki MN, Obuchowski N, Modic MT, Malkasian D, Ross JS.
   Magnetic Resonance Imaging of the Lumbar Spine in People Without Back Pain. NEJM (1994).
   PubMed |
   Full text
3. Chiu CC, Chuang TY, Chang KH, Wu CH, Lin PW, Hsu WY.
   The probability of spontaneous regression of lumbar herniated disc: a systematic review. Clin Rehabil (2015).
   PubMed
4. Santilli V, Beghi E, Finucci S.
   Chiropractic manipulation in the treatment of acute back pain and sciatica with disc protrusion: a randomized double-blind clinical trial. Spine J (2006).
   PubMed
5. McMorland G, Suter E, Casha S, du Plessis SJ, Hurlbert RJ.
   Manipulation or microdiskectomy for sciatica? A prospective randomized clinical study. J Manipulative Physiol Ther (2010).
   PubMed
6. Ahmed I, et al.
   Effectiveness of Low-Level Laser Therapy in Patients with Discogenic Lumbar Radiculopathy. (2022).
   PubMed |
   Full text (PMC)
7. Konstantinovic LM, Cutovic MR, Milovanovic AN, et al.
   Low-level laser therapy for acute neck pain with radiculopathy: a double-blind placebo-controlled randomized study. Pain Med (2010).
   PubMed
8. Weishaupt D, Schmid MR, Zanetti M, et al.
   Positional MR imaging of the lumbar spine: does it demonstrate nerve root compromise not visible at conventional MR imaging? Radiology (2000).
   PubMed
9. Nguyen HS, Doan N, Gelsomino M, Shabani S.
   Upright magnetic resonance imaging of the lumbar spine: Back pain and radiculopathy. (2016).
   Full text (PMC)
10. Dydyk AM, et al. (StatPearls).
    Disk Herniation. NCBI Bookshelf (updated regularly).
    NCBI Bookshelf
11. Rothman SM, Winkelstein BA.
    Chemical and mechanical nerve root insults induce differential behavioral sensitivity and glial activation. (2007).
    Full text (PMC)
12. Peng B.
    Chemical radiculitis. (review).
    Abstract (ScienceDirect)

Note: Research links are for education. Your diagnosis and next steps should be based on your symptoms and exam, not MRI words alone.