Atresia is a condition in which an

orifice An orifice is any opening, mouth, hole or vent, as in a pipe, a plate, or a body * Body orifice, any opening in the body of a human or animal *Orifice plate, a restriction used to measure flow or to control pressure or flow, sometimes given specia ...

or passage in the body is (usually abnormally) closed or absent. Examples of atresia include: *

Aural atresia Microtia is a congenital deformity where the auricle (external ear) is underdeveloped. A completely undeveloped pinna is referred to as anotia. Because microtia and anotia have the same origin, it can be referred to as microtia-anotia. Microti ...

, a congenital deformity where the ear canal is underdeveloped. *

Biliary atresia Biliary atresia, also known as extrahepatic ductopenia and progressive obliterative cholangiopathy, is a childhood disease of the liver in which one or more bile ducts are abnormally narrow, blocked, or absent. It can be congenital or acquired. I ...

, a condition in newborns in which the common bile duct between the liver and the small intestine is blocked or absent. *

Congenital bronchial atresia A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...

, a rare congenital abnormality * Choanal atresia, blockage of the back of the nasal passage, usually by abnormal bony or soft tissue. *

Esophageal atresia Esophageal can refer to: * The esophagus * Esophageal arteries * Esophageal glands * Esophageal cancer Esophageal cancer is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include ...

, which affects the alimentary tract and causes the esophagus to end before connecting normally to the stomach. *

Follicular atresia Follicular atresia refers to the process in which a follicle fails to develop, thus preventing it from ovulating and releasing an egg. It is a normal, naturally occurring progression that occurs as mammalian ovaries age. Approximately 1% of mamma ...

, degeneration and resorption of the ovarian follicles. *

Imperforate anus An imperforate anus or anorectal malformations (ARMs) are birth defects in which the rectum is malformed. ARMs are a spectrum of different congenital anomalies which vary from fairly minor lesions to complex anomalies. The cause of ARMs is unkno ...

, malformation of the opening between the rectum and anus. *

Intestinal atresia Intestinal atresia is any congenital malformation of the structure of the intestine that causes bowel obstruction. The malformation can be a narrowing (stenosis), absence or malrotation of a portion of the intestine. These defects can either occur ...

, malformation of the intestine, usually resulting from a vascular accident in utero. *

Microtia Microtia is a congenital deformity where the auricle (external ear) is underdeveloped. A completely undeveloped pinna is referred to as anotia. Because microtia and anotia have the same origin, it can be referred to as microtia-anotia. Microti ...

, absence of the ear canal or failure of the canal to be tubular or fully formed (can be related to

, a congenital deformity of the pinna, or outer ear). * Ovarian follicle atresia, the degeneration and subsequent resorption of one or more immature

ovarian follicle An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. At the time of puberty, women have approximately 200,000 to 300,000 follicles, each with ...

s. * Potter sequence, congenital decreased size of the kidney leading to absolutely no functionality of the kidney, usually related to a single kidney. *

Pulmonary atresia Pulmonary atresia is a congenital malformation of the pulmonary valve in which the valve orifice fails to develop. The valve is completely closed thereby obstructing the outflow of blood from the heart to the lungs. The pulmonary valve is located ...

, malformation of the pulmonary valve in which the valve orifice fails to develop. *

Renal agenesis Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop. Unilateral and bilateral renal agenesis in humans, mice and zebra fish has been linked to mutations in the gene GREB1L. It has als ...

, only having one kidney. * Tricuspid atresia, a form of congenital heart disease whereby there is a complete absence of the tricuspid valve, and consequently an absence of the right atrioventricular connection. *

Vaginal atresia Vaginal atresia is a condition in which the vagina is abnormally closed or absent. The main causes can either be complete vaginal hypoplasia, or a vaginal obstruction, often caused by an imperforate hymen or, less commonly, a transverse vaginal se ...

, a congenital occlusion of the vagina or subsequent adhesion of the walls of the vagina, resulting in its occlusion.

References

Medical terminology Anatomy {{Disease-stub