Subluxation

What it means

A subluxation is a partial loss of alignment at a joint. The two bones that meet there have shifted out of their proper position, but unlike a full dislocation they are still partly in contact. Think of it as a joint that has slipped, rather than one that has come fully apart. It can happen at small joints, like those in the spine or fingers, or at large ones, like the shoulder or kneecap, and it may be momentary or lasting.

Why it appears on a CT, MRI or X-ray report

Radiologists report subluxation when the bones of a joint do not line up the way they should, but the joint surfaces still overlap to some degree. They describe which joint is affected, the direction of the slip, and how far it has moved, and they often compare it with full dislocation, which has its own meaning. They may also note what is allowing the slip — worn or stretched ligaments, an old injury, joint wear, or instability — since the cause shapes what it means.

What it usually means

The significance of a subluxation depends on the joint and the cause. Some subluxations are mild, long-standing, and produce few symptoms — for example small degrees of slip between spinal bones from age-related wear, which are common and often managed conservatively. Others matter more: a shoulder or kneecap that repeatedly subluxes can be unstable and prone to further slipping or full dislocation, and a subluxation after a significant injury can signal damaged ligaments that may need treatment. In the spine, more pronounced slips can narrow the channels for nerves and cause symptoms. Because subluxation is a partial version of dislocation, it is generally less of an emergency than a full dislocation, but it is still a real misalignment that often points to instability or injury rather than a normal joint. The details in the report determine how much it matters.

When to follow up

Be guided by the report and your symptoms. A small, stable, degenerative subluxation noted incidentally may simply be monitored and managed with strengthening and conservative care. A subluxation after injury, one that keeps recurring, or one causing pain, instability, numbness, tingling, or weakness should be reviewed by a doctor, sometimes with further imaging or referral to orthopaedics or physiotherapy. Seek prompt care for a joint that feels unstable, locks, gives way, or is associated with new limb weakness or loss of bladder or bowel control.

A plain-language way to picture it

Picture a desk drawer that has slipped off one of its runners. It is no longer sitting squarely, it sticks out at an angle and does not glide properly, but it has not fallen all the way out of the cabinet — one side is still hooked on. A subluxation is a joint in that half-off state: shifted out of true and not working smoothly, but still partly connected, somewhere between properly seated and completely out.