from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The absence or closure of a normal body orifice or tubular passage such as the anus, intestine, or external ear canal.
  • noun The degeneration and resorption of one or more ovarian follicles before a state of maturity has been reached.

from The Century Dictionary.

  • noun The state or condition of being closed or imperforate; specifically, absence of a natural opening or passage: chiefly used in medicine and surgery.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Med.) Absence or closure of a natural passage or channel of the body; imperforation.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun pathology A condition in which a body orifice or passage in the body is abnormally closed or absent.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun an abnormal condition in which a normal opening or tube in the body (as the urethra) is closed or absent


from The American Heritage® Dictionary of the English Language, 4th Edition

[New Latin atrēsia : Greek a-, not, without; see a– + Greek trēsis, perforation, orifice; see terə- in Indo-European roots.]


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  • Tricuspid atresia is usually diagnosed a few hours or days after birth.

    Tricuspid Atresia

  • Although biliary atresia is rare, its geographic reach is wide.

    Biliary Atresia Clinical Care Program

  • In general the long-term outlook for biliary atresia is excellent.

    Long-Term Outlook

  • Tricuspid atresia is a single-ventricle lesion, because the heart has only one functioning ventricle (the left ventricle).

    Tricuspid Atresia

  • Now with the Kasai hepatoportoenterstomy and improvements in liver transplantation, the first generation of patients with biliary atresia is reaching adulthood.

    Long-Term Outlook

  • The surgery for biliary atresia is called a Kasai operation or hepatoportoenterstomy.

    Frequently Asked Questions about Biliary Atresia

  • Biliary atresia is associated with several malformations including a malformation of the spleen, i.e. asplenia or polysplenia.

    Biliary Atresia Glossary

  • The purpose of surgery for children with biliary atresia is to restore bile flow.

    Frequently Asked Questions about Biliary Atresia

  • Biliary atresia is a serious liver disorder that occurs shortly after birth when a newborn's bile ducts (the tubes that carry bile from the liver) become blocked.

    About Biliary Atresia

  • Tricuspid atresia is often associated with pulmonary stenosis or narrowing of the pulmonary valve, or pulmonary atresia where the pulmonary valve is completely closed.

    Tricuspid Atresia


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