The outflow tract of the heart--embryologic and morphologic correlations

Int J Cardiol. 1989 Mar;22(3):289-300. doi: 10.1016/0167-5273(89)90270-2.


The separation process of the heart by which two great arteries and two outflow tracts are formed, was studied microscopically in 20 human embryos, ranging from 6 to 28 mm crown-rump length and macroscopically in eight hearts, ranging from 28 weeks of gestation to 80 years of age. The proximal (primary fold) and distal (ventriculo-arterial junction) borderlines of the outlet segment of the embryonic heart are important landmarks in this process. The remarkable, curved and twisted configuration of the ventriculo-arterial junction implies that the position of the arterial orifices, as well as the relative dimensions of the corresponding outflow tracts, are, already in a very early stage, similar to those in the fully developed heart. It furthermore implies that the separation by the aorto-pulmonary septum starts at this level and immediately involves the outlet segment where the two columns of the aorto-pulmonary septum mobilize the myocardium to form the posterior wall of the right ventricular outflow tract, rather than a septum between both outflow tracts. These findings make the morphology of the outflow tract of the normal heart comprehensible from a developmental point of view and throw a new light upon the morphogenesis of outflow tract malformations.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Heart / anatomy & histology
  • Heart / embryology*
  • Heart Septal Defects / embryology*
  • Heart Septal Defects / etiology
  • Heart Septal Defects / pathology
  • Humans
  • Infant
  • Infant, Newborn
  • Middle Aged
  • Myocardium / pathology