Internodal bundles

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The internodal bundles conduct electrical excitation in the right atrium from the sinus node to the AV node . The name “internodal” means “between the nodes” (from the Latin nodus “node”). TN James discovered them during anatomical and histological examinations on the human heart. The existence of the internodal bundle is controversial.

anatomy

The internodal bundles are part of the specific conduction system . In the normal heart, three fiber lines arise from the sinus node:

  • The front internodal bundle (Bachmann-James bundle) branches out from the same trunk as the Bachmann bundle . It attracts diagonally below the right atrial appendage in the atrium posterior wall down.
  • The middle internodal bundle ( Wenckebach bundle) runs above the fossa ovalis .
  • The posterior internodal bundle (Thorelian bundle) accompanies the crista terminalis in a caudal direction. It rises between the folds of the mouth of the lower vena cava (Eustachii) and the coronary sinus (Thebesii) in the floor of the atrium.

All internodal bundles terminate in the atrioventricular (AV) node. They serve to transfer the sinus impulse to the AV node. The excitation spreads through complicated intra- and intercellular processes in the right atrium.

literature

  • Frank Henry Netter : Color Atlases of Medicine. = The Ciba collection of medical illustrations. Volume 1: Martin Stauch (Ed.): Heart. Thieme, Stuttgart et al. 1976, ISBN 3-13-524001-0 .
  • Thomas N. James: The connecting pathways between the sinus node and AV node and between the right and left atrium in the human heart. In: American Heart Journal. Vol. 66, No. 4, 1963, pp. 498-508, doi : 10.1016 / 0002-8703 (63) 90382-X .