atresia and stenosis

Absence (atresia), usually congenital, or narrowing (stenosis) of almost any normal body cavity or passage. The more important include atresia of the anus, esophagus, aortic arch, heart valves, and urinary passages; and stenosis of the intestine, urinary passages, pyloric valve (stomach outlet), and heart valves. Most must be surgically corrected soon after birth.

Learn more about atresia and stenosis with a free trial on Britannica.com.

Examples of atresia include:

• Anorectal atresia - malformation of the opening between the rectum and anus.
• Aural atresia (see Microtia) - a congenital deformity of the pinna (outer ear).
• Biliary atresia
• Choanal atresia - blockage of the back of the nasal passage, usually by abnormal bony or soft tissue.
• Esophageal atresia - affects the alimentary tract causing the esophagus to end before connecting normally to the stomach.
• Intestinal atresia - malformation of the intestine
• Ovarian follicle atresia, atresia refers to the degeneration and subsequent resorption of one or more immature ovarian follicles.
• Pulmonary atresia - malformation of the pulmonary valve in which the valve orifice fails to develop.
• Tricuspid atresia - a form of congenital heart disease whereby there is a complete absence of the tricuspid valve. Therefore, there is an absence of right atrioventricular connection.
• Vaginal atresia - congenital occlusion (blocking) of the vagina or subsequence adhesion (sticking together) of the walls of the vagina occluding it.
• Renal Atresia - congenital decreased size of the kidney leading absolute no functionality of the kidney .It is usually related to a single kidney.