title: The thebesian circulation to developing conducting tissue: a nutrient-nodal hypothesis of cardiogenesis.
abstract: BACKGROUND
  In a previous paper the authors suggested that the right atrial appendage is structured for retrograde sinusoidal blood flow to embryonic conducting tissue in the venous sinus portion of the right atrium.
  
  
  OBJECTIVE
  To test the hypothesis that the relationship among conducting, valvar and trabecular myocardium of the human heart is primarily for the nutrition of the heart itself rather than for downstream blood flow.
  
  
  METHODS
  Embryonic, fetal, infant and adult human hearts were studied grossly and microscopically for evidence of a dedicated sinusoidal blood supply to the atrioventricular node. Outflow tract anatomy was reviewed to test the hypothesis that junctional zones, nodal or non-nodal, are structured according to the same basic principle concerning nutrient supply to conducting tissue.
  
  
  CONCLUSIONS
  The finding of a sinusoid-rich 'spongy trabecula' in relation to the septal node suggests that the septal junctional zone, like the sinoatrial junctional zone, is structured for retrograde sinusoidal blood flow to nodal conducting tissue. The anatomy of the pulmonary and aortic outflow tracts supports the idea that the heart is structured from repeating triplets of conducting, valvar and sinusoid-rich trabeculae. Although the heart is an external pump, it is structured as an internal pump.
authors.affiliation: Health Sciences Centre, Winnipeg, Canada. John_Taylor@videon.wave.ca
authors.forename: J R
authors.initials: JR
authors.lastname: Taylor
authors.forename: A J
authors.initials: AJ
authors.lastname: Taylor
mesh_terms: D000328:Adult; D001283:Atrioventricular Node / Q000196:embryology* / Q000473:pathology; D002036:Bundle of His / Q000196:embryology / Q000473:pathology; D003331:Coronary Vessels / Q000196:embryology* / Q000473:pathology; D005260:Female; D005318:Fetal Heart / Q000473:pathology; D005865:Gestational Age; D006325:Heart Atria / Q000196:embryology / Q000473:pathology; D006346:Heart Septum / Q000196:embryology / Q000473:pathology; D006352:Heart Ventricles / Q000196:embryology / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D013398:Sudden Infant Death / Q000473:pathology