Spine MRI Report Glossary: What the Words Mean - Spinal DISC Center | Kris Radcliff, MD | New Jersey

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Spine MRI Report Glossary: What the Words Mean

MRI reports are written for doctors. Patients often read them first, look up the words, and get scared. This glossary explains the words you are most likely to see in a spine MRI report, in plain language.

A quick note on “standard” words. Only some report words have an official, agreed definition, set by the national spine and radiology societies (the North American Spine Society, the American Society of Spine Radiology and the American Society of Neuroradiology). Many other common words have no agreed meaning, so one reader’s “mild” can be another reader’s “moderate.” Each term below is marked:

Standard means there is an agreed definition or a published grading system.
No agreed definition means the word is common but its meaning varies from reader to reader.

Many of these findings are also common in people with no pain at all. An MRI finding only matters if it matches your symptoms and your exam.

Disc words

Disc Standard: The cushion between two spine bones. It has a tough outer ring (the annulus) and a soft, jelly-like center (the nucleus). Think of a jelly donut.

Disc bulge Standard: The disc spreads out evenly around more than a quarter of its edge, like a squished donut. The jelly stays inside. A bulge is not a herniation. Bulges are very common with age and often cause no pain.

Disc herniation Standard: Disc material pushes out beyond its normal edge in one area (less than a quarter of the edge). Protrusion, extrusion and sequestration are the three types.

Protrusion Standard: A type of herniation where the bump is wider at its base than it is tall. The jelly pushes the wall out but does not escape far.

Extrusion Standard: A type of herniation where the piece that pushed out is bigger than the opening it came through, or has moved up or down. Extrusions are the type most likely to pinch a nerve and cause arm or leg pain.

Sequestration (free fragment) Standard: A piece of disc has broken off completely and is loose in the spinal canal.

Migration Standard: Disc material has moved up or down from the disc space.

Broad-based herniation Standard: A herniation covering about a quarter to a half of the disc edge. Sometimes reports call this a “bulge,” which can make it sound less important than it is.

Annular fissure (annular tear) Standard: A crack in the outer ring of the disc. “Fissure” is the preferred word because “tear” suggests an injury, and most fissures come from normal wear. On MRI a bright spot called a “high-intensity zone” may mark it.

Disc degeneration, desiccation, dehydration, loss of disc height No agreed definition, unless a Pfirrmann grade is given: The disc has dried out and may be flatter. These words overlap and are used differently by different readers. The Pfirrmann scale (grades 1 to 5) is the published system for grading this.

Degenerative disc disease No agreed definition: Not really a disease. It usually means age-related wear in the discs.

Disc-osteophyte complex No agreed definition: Disc material and bone spur together. It is not part of the official disc vocabulary. On a standard MRI, soft disc and hard bone can be hard to tell apart, so this phrase often means “we cannot tell which it is.” A CT scan can help.

Modic changes (type 1, 2 or 3) Standard: Changes in the bone right next to a disc. Type 1 is swelling, type 2 is fatty change, and type 3 is hardening of the bone.

Narrowing (stenosis) words

Spinal stenosis Standard as a concept: Narrowing of the spaces where the nerves travel. It can be in the center of the canal, at the sides, or where the nerves exit.

Central canal stenosis: Narrowing of the main tunnel in the middle of the spine. Published grading systems include the Schizas and Lee scales.

Lateral recess (subarticular) stenosis: Narrowing along the sides of the canal, where a nerve root travels before it exits.

Foraminal stenosis (foraminal narrowing): Narrowing of the small opening where a nerve leaves the spine. The Lee scale is the most widely tested system, but foraminal grading is still less consistent than central grading.

Mild, moderate, severe No agreed definition unless a named scale is used: This is the most important one to understand. Unless the report names a grading system (such as Schizas or Lee), these words are the reader’s impression. One reader’s “moderate” can be another’s “severe.”

Canal compromise, crowding, narrowing No agreed definition: General words for less room for the nerves, with no set size.

Thecal sac Standard: The fluid-filled sleeve that holds the nerves inside the spinal canal.

Effacement No agreed definition: Something presses on and flattens the fluid space around the nerves. How much is not defined.

Nerve words

Nerve root Standard: A nerve branch leaving the spine to go to an arm or leg.

Contact, abutment, touching, indentation, impingement No agreed definition: These words describe something near or against a nerve, but readers use them for anything from “close by” to “pushing on it.” Research has found that a disc simply touching a nerve can cause as much leg pain as one displacing it, so “just abutting” does not always mean “not important.”

Compression No agreed definition: Something is pressing on a nerve or the spinal cord. How much is up to the reader unless measured.

Cauda equina Standard: The bundle of nerves at the bottom of the spinal canal. Severe pressure here (cauda equina syndrome) is an emergency.

Cord compression Standard as a concept: Pressure on the spinal cord in the neck or upper back.

Myelomalacia, cord signal change Standard: A change inside the spinal cord that can mean it has been injured by pressure. This finding deserves prompt attention.

Radiculopathy Standard: A pinched or irritated nerve root causing pain, numbness, tingling or weakness in an arm or leg. Sciatica is radiculopathy in the leg.

Myelopathy Standard: A problem with the spinal cord itself, which can cause clumsy hands, trouble walking or balance problems.

Joint and bone words

Facet joints Standard: Small joints on the back of the spine that let you bend and twist.

Facet arthropathy, facet hypertrophy, facet arthritis No agreed definition for severity: Wear and enlargement of the facet joints. Readers often disagree on how bad it is.

Ligamentum flavum thickening (hypertrophy): A ligament at the back of the canal has thickened, which can narrow the canal.

Osteophyte (bone spur) Standard: Extra bone that forms with arthritis.

Spondylosis No agreed definition: An umbrella word for general wear and arthritis of the spine.

Spondylolisthesis Standard, graded by the Meyerding scale: One spine bone has slipped forward on the one below. Anterolisthesis means forward; retrolisthesis means backward.

Spondylolysis (pars defect) Standard: A crack in a small bridge of bone at the back of the spine, which can lead to slipping.

Pseudo-disc (uncovering): When a bone slips, the disc can look like it is sticking out even when it is not truly herniated. These levels are sometimes over-called as herniations.

Endplate Standard: The top or bottom surface of a spine bone, next to the disc.

Compression fracture Standard: A spine bone has partly collapsed, often from weak bones (osteoporosis) or an injury.

Schmorl’s node Standard: Disc material has pushed into the bone above or below. Common and usually harmless.

Hemangioma Standard: A common, harmless spot of blood vessels inside a spine bone.

Scoliosis Standard: A sideways curve of the spine.

Kyphosis / lordosis Standard: The normal forward and backward curves of the spine. Reports may say they are increased, decreased or “straightened.”

Report language

Shallow, small, minimal, tiny, minor No agreed definition: Size words with no measurement behind them. Ask for the size in millimeters if it matters.

Degenerative changes No agreed definition: General wear. Common in people with no pain.

Clinical correlation recommended: The reader is saying the finding needs to be matched to your symptoms and exam by your doctor.

Appears, likely, possibly represents, cannot exclude: Hedging words. The reader is not certain.

Unremarkable: Normal-looking.

Artifact: Something in the picture that is not really in your body, often from motion or metal.

T1, T2, STIR: Different types of MRI pictures. Each shows tissues in a different way. STIR is good at showing swelling.

How common are these findings in people with no pain?

A large review of MRI studies in people with no back pain found disc bulges in about 30% of 20-year-olds and 84% of 80-year-olds, and disc protrusions in about 29% of 20-year-olds and 43% of 80-year-olds. In the neck, one large study of people with no symptoms found disc bulges in most of them, but spinal cord compression in only about 5%. This is why the images must be matched to your symptoms and exam.

Bring your actual images, not just the report. Dr. Radcliff reviews the images himself at every visit. You can send your MRI images for a review or call 609-800-3472.

Sources include the Lumbar Disc Nomenclature 2.0 (Fardon et al., Spine 2014), Brinjikji et al. (AJNR 2015), Nakashima et al. (Spine 2015) and Walsh et al. (Academic Radiology 2026). This page is for general education and is not medical advice.