What does "Foraminal stenosis" mean?

Foraminal stenosis is a narrowed exit door

The foramen is the doorway a nerve root uses to leave your spine. Foraminal stenosis means that doorway is narrower than usual.

Why it is usually one-sided

There is a foramen on each side at every level. Narrowing tends to affect one, which is why symptoms usually appear in one arm or one leg rather than both.

What narrows it

A disc losing height reduces the space from above and below. A disc bulging backward and sideways reduces it from the front. Enlarged facet joints reduce it from behind. Often it is a combination, built up slowly.

Why the level matters

Your report names a level — L4-L5, L5-S1, C6-C7. Each level serves a specific region, so the named level and the location of your symptoms should agree. When they do not, the finding may not be the explanation.

The part that usually gets left out

Foraminal narrowing is extremely common on imaging in people without symptoms, and it is not a measure of how much trouble you are in.

Brinjikji et al., systematic review of imaging in asymptomatic populations (AJNR, 2015).

What it does not mean

It does not mean the nerve is trapped for good.
It does not mean the narrowing is what is causing your pain — the level and the symptoms have to match.

When to stop reading and see someone

Seek urgent medical care

Loss of bladder or bowel control, or numbness around the groin and inner thighs (possible cauda equina syndrome)

See a professional before continuing

Most back pain is not dangerous. These signs, though, need a person — not a web page:

Pain after significant trauma — a fall or an accident
Neurological deficit: loss of strength, loss of sensation, or spreading numbness
Fever, chills, or signs of infection alongside back pain
Unexplained weight loss, or a history of cancer
Severe night pain that does not settle with rest
Pregnancy — back pain in pregnancy needs specialised guidance
Under 18 years old — this content is written for adults

This page explains the term. The app explains your report.

Every report is worded differently — the level, the wording, whether a nerve is involved. SpinalAI reads your own report and tells you what yours says, in plain English, in seconds.

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Written from published research and reviewed for safety. Not yet reviewed by a named clinician — we say so rather than imply otherwise.