Atresia

Atresia is a condition in which a body orifice or passage in the body is abnormally closed or absent.

Examples of atresia include:

• Imperforate anus - malformation of the opening between the rectum and anus.
• Microtia- Absence of the ear canal or failure of the canal to be tubular or fully formed (can be related to Microtia- a congenital deformity of the pinna (outer ear).)
• Biliary atresia - Condition in newborns in which the common bile duct between the liver and the small intestine is blocked or absent.
• 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, usually resulting from a vascular accident in utero
• 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 of the vagina or subsequence adhesion of the walls of the vagina occluding it.
• Potter sequence - congenital decreased size of the kidney leading absolute no functionality of the kidney, usually related to a single kidney.
• Aural Atresia - refers to the absence of an external ear canal, often with malformation of the external, middle, and/or inner ear. It can be a symptom of other syndromes (Hemifacial Microsomia, 18-q chromosome, and several others).