QS Study

Moderator band

Synonym – Septomarginal trabeculae.

It is a muscular ridge extending from the lower part of the ventricular septum to the base of the anterior papillary muscle, from the lower limit of the inflow tract. It is a regular structure in the morphologic right ventricle and can be obliging as a landmark in situations where the ventricles may be ambiguous. It does not attach to the tricuspid valve but acts as part of the electrical conduction pathway of the heart. It is a small muscular band that covers a nerve bundle.

Fig: Moderator Band


  • Prevents ventricular overdistension.
  • It contains a continuation of the right bundle branch of conducting tissue.
  • To facilitate the conduction time thereby allowing coordinated contraction of the anterior papillary muscle.
  • For effective Cardiac Output because it helps in a coordinated contraction of ventricular cells.

Moderator band is often used by radiologists and obstetricians to more easily identify the right ventricle in prenatal ultrasound.

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