Definition of Atresia

Atresia is a condition in which a body orifice or passage in the body is abnormally closed or completely absent. Atresia can affect many structures in the body, including:

  • Anal atresia -- congenital absence of the anus (also called imperforate anus).
  • Aortic atresia -- congenital absence of the valvular opening into the aorta.
  • Biliary atresia -- absence of the major bile ducts.
  • Choanal atresia -- congenital failure of nasal passages to open.
  • Esophageal atresia -- a birth defect in which part of esophagus is not hollow.
  • Intestinal atresia -- obliteration of the hollow of the small intestine, involving the ileum or the jejunum or duodenum.
  • Laryngeal atresia -- congenital failure of the laryngeal opening to develop.
  • Pulmonary atresia -- congenital absence of the pulmonary valve opening in the heart.
  • Tricuspid atresia -- congenital lack of the tricuspid valve opening.
  • Vaginal atresia -- congenital occlusion of the vagina or subsequence adhesion of the walls of the vagina occluding it.