1. A normally or pathologically constricted or narrowed portion of a luminal structure. See also stricture, stenosis. 2. The act or process of binding or contracting, becoming narrowed; the condition of being constricted. squeezed. 3. A subjective sensation of pressure or tightness, as if the body or any part were tightly bound or squeezed. [L. con-stringo, pp. -strictus, to draw together]
esophageal c.'s three narrowings of the esophagus normally demonstrated radiographically following a barium swallow: the upper or pharyngeal esophageal constriction, at the beginning of the esophagus, is caused by the cricopharyngeus muscle, often referred to as the superior esophageal sphincter; the middle or aortic constriction is a left-sided narrowing due to the esophagus passing the aortic arch; the inferior or diaphragmatic esophageal c. corresponds to the passage of the esophagus through the esophageal hiatus of the diaphragm.impressions of esophagus;
primary c. the narrowing between the two arms of the chromosome represented by the centromere.
pyloric c. a prominent fold of mucous membrane at the gastroduodenal junction overlying the pyloric sphincter.pyloric valve, valvula pylori, valvulae pylori;
secondary c. a subsidiary narrowing of the chromosome associated in some cases with satellites.
c.'s of ureter normal physiological narrowings of the ureter observable in a pyelogram; the uppermost occurs at the origin of the ureter from the renal pelvis; a second occurs as the ureter crosses the iliac vessels and pelvic brim; the inferiormost occurs as the ureter penetrates the wall of the urinary bladder.
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