What it means
Stenosis is abnormal narrowing of a tube, vessel, valve or canal. A stricture is essentially the same thing, the term used more often for the gut and urinary tract.
Common examples:
- Aortic stenosis — narrowing of the heart valve, causing breathlessness, chest pain and blackouts on exertion
- Carotid stenosis — narrowing of the neck artery supplying the brain, raising stroke risk
- Spinal stenosis — narrowing of the spinal canal, causing leg pain on walking that eases on bending forward
- Pyloric stenosis — narrowing of the stomach outlet, classically in infants
In practice
Graded as mild, moderate or severe on imaging, with the grade usually determining whether intervention is warranted.
Spinal stenosis produces a characteristic pattern in which walking uphill or pushing a trolley is easier than walking upright, because flexion opens the canal.
Why it matters
The significance depends on the site. Aortic stenosis causing breathlessness, chest pain or blackouts on exertion is serious and warrants prompt cardiology assessment, as valve replacement is highly effective.
Spinal stenosis is usually managed conservatively, with surgery reserved for significant limitation of walking distance.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026