Vertebra
Read Your Scan Editorial Team·Last updated
Written from published radiology references and reviewed for plain language. Not written or signed by a physician, and not a diagnosis. How we write these pages →
In plain language
One of the stacked bones that make up the spine. In the low back these are labeled L1 through L5.
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Where you'll see this
This wording turns up on Lumbar Spine MRI reports — MRI imaging of the spine. A lumbar (low-back) MRI shows the vertebrae, the cushioning discs between them, the spinal canal, and the nerves that travel to the legs. Doctors order it for low-back pain, sciatica, leg numbness or weakness, or to plan care. Importantly, many of the changes it describes are extremely common and are seen in people with no pain at all — so the report is read together with how you actually feel.
Questions worth asking your doctor
- Do the findings on the MRI match where I actually feel pain or symptoms?
- Are these changes common for my age, or is anything unusual?
- What are my non-surgical options, such as physical therapy?
- Are there any signs that would mean I should seek care sooner?
- Do I need any follow-up imaging, and when?
How common is this?
The vertebrae are the individual bones of the spine, and they are named throughout every spine report — usually by level, such as L4 or C5. The numbering is one of the most useful things to understand about a spine report, because almost every finding is located by naming the vertebrae or the disc between two of them.
When should I worry?
The naming itself is anatomy. What is worth knowing is how to read a level: C is cervical in the neck, T is thoracic in the mid back, L is lumbar in the lower back, and S is sacral. A disc is named for the two vertebrae it sits between, so L5-S1 is the disc between the last lumbar vertebra and the top of the sacrum — the level involved in a large share of lower back problems. Findings described about the vertebral bodies themselves, such as height loss or marrow changes, are separate matters and are described in their own language.
What happens next
Nothing follows from the naming. Its practical value is in reading your own report accurately and in asking a specific question at an appointment. Knowing that a finding sits at L5-S1 rather than somewhere unspecified lets you ask whether that level matches the distribution of your symptoms, which is exactly the correlation the report has handed to your doctor.
Frequently asked questions
- What do the letters and numbers mean?
- The letter is the region — C for the neck, T for the mid back, L for the lower back, S for the sacrum — and the number is the position within it, counted from the top. C5 is the fifth vertebra down in the neck.
- What does L5-S1 mean?
- The disc space between the fifth lumbar vertebra and the first sacral segment. It is the lowest mobile level of the lumbar spine and one of the most commonly involved in disc problems.
- Why does the level matter?
- Because each nerve root serves a particular area of the body. Matching the level of a finding to where symptoms are felt is how a doctor decides whether an image explains what you are experiencing.
Other words on the same report
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Read Your Scan is informational only — not a medical diagnosis, and not a substitute for a licensed radiologist or your doctor. If you have urgent symptoms, seek care.