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Medical Term:

interatrial foramen primum


  1. in the embryonic heart, the temporary opening between right and left atria situated between the lower margin of the septum primum and the atrioventricular canal cushions;
  2. in an adult heart, the abnormal persistence of the so-named communication, which is normal in young embryos.

Synonym(s): foramen subseptale, ostium primum, primary interatrial foramen

© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.