Cartilage
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
The smooth, slippery surface covering the ends of bones so they glide easily in the joint.
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Where you'll see this
This wording turns up on Knee MRI reports — MRI imaging of the knee. A knee MRI is very good at showing soft tissues that X-rays cannot, including the menisci (the knee’s cushions), the major ligaments, the tendons, the joint cartilage, and the bones. Doctors order it after an injury, for pain, swelling, locking, or instability, or to plan treatment. Some findings, like mild wear, are common with age and may not be the source of symptoms — your doctor connects the images to your exam.
Questions worth asking your doctor
- Do the MRI findings explain the pain, swelling, or instability I feel?
- Is any finding likely age-related rather than from a recent injury?
- What are my treatment options, including non-surgical ones?
- Would physical therapy help before considering other steps?
- Do I need any follow-up, and when should I check back?
How common is this?
Cartilage is named in nearly every joint report, because it is the surface that makes a joint work. It is the smooth, slippery, low-friction layer covering the ends of bones, and it has no nerve supply and almost no blood supply — which is why it cannot hurt directly and why it repairs so poorly once damaged.
When should I worry?
A key practical point: cartilage is invisible on X-ray. What an X-ray shows is the gap between bones, and joint space narrowing is an indirect inference that the cartilage between them has thinned. MRI shows it directly, which is why MRI reports describe its thickness and surface in a way X-ray reports cannot. Thinning is extremely common with age and correlates poorly with pain — plenty of people have marked thinning with no symptoms, and plenty have severe pain with cartilage that looks reasonable. What is treated is how the joint behaves, not how the surface looks.
What happens next
For the common picture of age-related thinning, treatment is not aimed at the cartilage, because there is no reliable way to regrow it. It targets the things that actually change outcomes: strengthening the muscles that support and unload the joint, managing weight and activity, and pain control. That approach works well for a large share of people despite the images staying exactly the same. Surgical options exist for specific situations, mainly focal defects in younger people rather than generalised wear.
Frequently asked questions
- Can cartilage grow back?
- Not meaningfully in adults. It has essentially no blood supply, which is what makes it so poor at healing. That is why treatment focuses on offloading and supporting the joint rather than on restoring the surface, and why claims about regrowing cartilage should be treated sceptically.
- Why does my X-ray not show the cartilage?
- Because X-rays image dense structures, and cartilage is not dense enough to appear. What is seen is the space between the bones, and a narrowed space is taken as indirect evidence that the cartilage has thinned. MRI shows the cartilage itself.
- Does cartilage damage always cause pain?
- No, and the mismatch is striking. Cartilage has no nerve supply, so damage to it cannot hurt directly — pain comes from the bone underneath, the joint lining and the surrounding structures. That is why images and symptoms so often disagree.
Other words on the same report
Where this word comes up
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