Stenosis

Stenosis is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture).

Stricture as a term is usually used when narrowing is caused by contraction of smooth muscle (e.g. achalasia, prinzmetal angina); stenosis is usually used when narrowing is caused by lesion that reduces the space of lumen (e.g. atherosclerosis). The term coarctation is another synonym, but is commonly used only in the context of aortic coarctation.

Restenosis is the recurrence of stenosis after a procedure.

Examples
Examples of vascular stenotic lesions include:
 * Intermittent claudication (peripheral artery stenosis)
 * Angina (coronary artery stenosis)
 * Carotid artery stenosis which predispose to (strokes and transient ischaemic episodes)
 * Renal artery stenosis

In heart valves
The types of stenoses in heart valves are:
 * Pulmonary valve stenosis, which is the thickening of the pulmonary valve, therefore causing narrowing
 * Mitral valve stenosis, which is the thickening of the mitral valve (of the left heart), therefore causing narrowing
 * Tricuspid valve stenosis, which is the thickening of the tricuspid valve (of the right heart), therefore causing narrowing
 * Aortic valve stenosis, which is the thickening of the aortic valve, therefore causing narrowing

Elsewhere
Stenoses/strictures of other bodily structures/organs include:
 * Pyloric stenosis (gastric outflow obstruction)
 * Lumbar, cervical or thoracic spinal stenosis
 * Subglottic stenosis (SGS)
 * Tracheal stenosis
 * Obstructive jaundice (biliary tract stenosis)
 * Bowel obstruction
 * Phimosis
 * Non-communicating hydrocephalus due to aqueductal stenosis
 * Stenosing tenosynovitis
 * Atherosclerosis
 * Esophageal stricture
 * Achalasia
 * Prinzmetal angina
 * Vaginal stenosis
 * Meatal stenosis

Causes

 * alcohol
 * atherosclerosis
 * birth defects
 * calcification
 * diabetes
 * headbanging
 * iatrogenic
 * infection
 * inflammation
 * ischemia
 * neoplasm
 * smoking
 * ureteral
 * urethral

Diagnosis
Stenoses of the vascular type are often associated with unusual blood sounds resulting from turbulent flow over the narrowed blood vessel. This sound can be made audible by a stethoscope, but diagnosis is generally made or confirmed with some form of medical imaging (such as ultrasound).