Stenosis

Stenosis is an abnormal narrowing of a bodily passage or opening that restricts the movement of blood, air, or other contents. It can affect structures such as arteries, heart valves, and the spinal canal.

Atherosclerosis: A disease in which lipid-rich plaques build up in arterial walls, narrowing arteries and sometimes limiting blood flow. Plaque buildup is a common cause of narrowing in arteries.
Spinal stenosis: Narrowing of spaces within the spine that can compress the spinal cord or nerve roots. It is a common form of stenosis with characteristic nerve-related symptoms.
Lumen: The interior space of a tubular structure, such as a blood vessel or the intestine. Stenosis reduces the space through which contents must pass.
Occlusion: The complete or near-complete blockage of a bodily passage or vessel. Stenosis narrows a passage; occlusion blocks it.
Fibrosis: The excessive formation of connective tissue that can stiffen or scar an organ or other body structure. Scar tissue can contract or thicken around a passage and reduce its opening.
Aortic stenosis: Narrowing of the aortic valve opening that obstructs blood flow from the left ventricle into the aorta. It shows how valve narrowing can obstruct the heart's outflow.
Blood flow: The movement of blood through the heart and blood vessels. A narrowed vessel can increase resistance and limit blood flow beyond it.
Regurgitation: The backward flow of blood through a heart valve that does not close properly. Valve stenosis restricts forward flow, whereas regurgitation permits backward flow.
Calcification: The accumulation of calcium salts in tissue, which can make it abnormally hard or stiff. Calcification can stiffen and narrow heart valves, especially the aortic valve.
Pulmonary stenosis: Narrowing at or near the pulmonary valve that impedes blood flow from the right ventricle to the lungs. This valve disorder illustrates stenosis in a different part of the heart.

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Surgically created structuresRelated: Narrowing can restrict flow through an anastomosis, stoma, or vascular access.