A stenosis (from Ancient Greek στενός, "narrow") is an abnormal narrowing in 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. Types
The resulting syndrome depends on the structure affected. 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 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 narrowingStenoses/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 causes stenotic lesions in arteries. birth defects
calcification
diabetes
headbanging – as in the case of Dave Mustaine
iatrogenic, e.g.
Although the patient may have a variety of other symptoms the diaphragmatic palsy confirmed by fluoroscopy or other means is the main criteria for diagnosis. This is usually confirmed with genetic testing looking for mutations in the IGHMBP2 gene. The patient can be misdiagnosed if the respiratory distress is mistaken for a severe respiratory infection or DMSA1 can be mistaken for SMA1 because their symptoms are so similar but the genes which are affected are different. This is why genetic testing is necessary to confirm the diagnosis of DMSA. Classification
DSMA1 was identified and classified as a sub-group of spinal muscular atrophies (SMA) in 1974. Currently, various classifications include DSMA1 among general spinal muscular atrophies or distal hereditary motor neuropathies, though the latter has been argued to be more correct. Treatment
There is no known cure to DSMA1, and care is primarily supportive. Patients require respiratory support which may include non-invasive ventilation or tracheal intubation. The child may also undergo additional immunisations and offered antibiotics to prevent respiratory infections. Maintaining a healthy weight is also important. Patients are at risk of undernutrition and weight loss because of the increased energy spent for breathing. Physical and occupational therapy for the child can be very effective in maintaining muscle strength.There is no published practice standard for the care in DSMA1, even though the Spinal Muscular Atrophy Standard of Care Committee has been trying to come to a consensus on the care standards for DSMA1 patients.