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the narrowing of a physiological opening or the lumen of a tubular organ. Examples of the former include stenosis of the left atrioventricular orifice of the heart, or mitral stenosis. Examples of the latter include stenosis of the intestine, trachea, bronchi, arteries, or pylorus of the stomach (pylorostenosis).
Stenoses may be congenital (developmental anomalies) or acquired, in which case they may be caused by a tumor or by scarring following an inflammatory process, ulcer, or trauma. Organic strictures are distinguished from functional stenoses, which result from a spasm of the musculature. Severe stenosis hampers the movement of blood, food, and air, and consequently the musculature of the organ located above the stenosis hypertrophies (compensated stenosis). Later, muscle tone decreases, the lumen of the organ above the stricture enlarges substantially, and the movement through the narrowed part becomes disrupted (decompensated stenosis).
Stenosis is treated surgically by enlarging the affected orifice, as in some cases of heart disease, by passing a bougie through the structure involved, by excising the constricted part, or by performing plastic surgery.