If you’ve ever opened your MRI report, you know it can feel like reading another language. Words like extrusion, spondylolisthesis, or ligamentum flavum thickening can look frightening when you don’t know what they mean.
Our goal here is simple: to explain common lumbar MRI terms in plain English, so you feel more confident discussing your results with your healthcare provider.
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A disc bulge means the outer wall of the disc is sticking out slightly, like a balloon pushing outward. Most bulges are broad-based and may not cause symptoms.
A protrusion is when part of the disc pushes out more distinctly, like a bump. It’s more focused than a bulge but the inner disc material is still contained.
This means the disc’s inner material has squeezed out through a weak spot in the outer wall. It can press on nearby nerves and cause pain, numbness, or sciatica.
An extrusion is a more advanced herniation — the inner disc material pushes out farther and has a narrow “neck” connecting it to the disc. It often has a greater chance of irritating nerves.
The annulus is the tough outer wall of the disc. A fissure (or annular tear) is a small rip in that wall. This may allow chemicals to leak out and irritate nerves, even without major compression.
This means one vertebra has slipped compared to the one below it.
Anterolisthesis = slipped forward.
Retrolisthesis = slipped backward.
Think of a tire:
If it’s fully aired up (healthy disc), it keeps bones stable.
If it’s flat (degenerated disc), bones can slide forward or backward — like a wheel wobbling on the rim.
This describes narrowing of the main spinal canal where the nerves travel. Severe cases can crowd nerves and cause leg pain, weakness, or heaviness when standing or walking.
The foramina are openings where spinal nerves exit. When discs bulge, bones thicken, or ligaments enlarge, these holes shrink, pinching nerves. This is a common cause of sciatica.
Facet joints are small stabilizing joints in the back of the spine. Arthropathy means arthritis or degeneration of those joints, which can cause stiffness, pain with twisting, or instability.
The ligamentum flavum runs along the back of the spinal canal. Over time, it can thicken like calloused skin, pushing into nerve space and worsening stenosis.
This is excess fat in the spinal canal. A little fat is normal, but too much can reduce space for nerves. Often linked to obesity, steroid use, or hormonal conditions.
The endplates are the edges of vertebral bones. With stress or arthritis, they can form spurs (osteophytes) that project into the disc space and may irritate nerves.
Normally, facet joints are symmetrical. Facet tropism means they are angled differently side-to-side. This can create uneven forces on the spine and contribute to early degeneration or instability.
This describes a spinal level that looks like a “hybrid” between two regions — for example, the lowest lumbar vertebra (L5) partly shaped like the sacrum. It can confuse numbering and sometimes affect mechanics of the spine.
A hemangioma is a benign (noncancerous) cluster of blood vessels inside a vertebral body. They are common “incidental findings” and usually harmless.
Radiologists describe Modic type I, II, or III changes in the bone next to discs. These represent different stages of inflammation, fat replacement, or sclerosis. Sometimes associated with back pain.
Many MRI findings are normal age-related changes — like wrinkles or gray hair.
What matters is whether those findings actually match your symptoms.
A “scary” MRI doesn’t always mean surgery — and sometimes even big findings can be managed conservatively.
If you’re dealing with symptoms from a herniated or bulging disc, see our detailed guide to herniated disc treatment in Plano to learn about non-surgical options.
Don’t panic when you see complex words on your MRI report.
Ask your provider which findings actually explain your pain.
Explore nonsurgical treatments like spinal decompression, chiropractic adjustments, and rehab before considering surgery.
At Frisco Spinal Rehab, we help patients make sense of their MRI results and offer advanced nonsurgical options like the DRX9000 spinal decompression system.
If you’d like help understanding your MRI and planning your recovery, schedule a consultation today.
Q: What’s the difference between a disc bulge, protrusion, and extrusion?
Bulge = broad, shallow pushing out of the disc.
Protrusion = a more focused bump.
Extrusion = disc material pushed farther out with a narrow “neck.”
Q: Is ligamentum flavum thickening dangerous?
By itself, no — but when combined with disc bulges or arthritis, it can narrow the spinal canal and press on nerves, worsening stenosis symptoms.
Q: What does facet arthropathy mean?
It’s simply arthritis in the small joints of the spine. Like knee arthritis, it can cause stiffness, grinding, and pain with movement.
Q: What is a transitional segment?
A spinal level that looks like a mix between lumbar and sacrum (or thoracic and lumbar). Often harmless but can sometimes affect mechanics or numbering on your MRI.
Q: Is a hemangioma in the spine serious?
Most spinal hemangiomas are benign and never cause symptoms. They’re usually “incidental findings” that don’t need treatment.
Disclaimer – This article is for educational purposes only and should not replace professional medical advice. MRI reports must always be interpreted in the context of your health history, symptoms, and physical exam. Please consult your doctor about your individual results.
