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Moderator band

Case contributed by Dr Matt A. Morgan

Patient Data

Age: 60-65 years
Gender: Male

The yellow arrow points to the moderator band in the right ventricle.

The second image shows spatial arrangement of the moderator band and anterior tricuspid papillary muscles. The yellow arrow points to the moderator band, stretching across the right ventricular cavity. The smaller brown arrow points to an anterior papillary muscle underneath. The right ventricle wall attachment of the moderator band joins the base of the anterior tricuspid papillary muscle.

Case Discussion

The moderator band, also called the septomarginal trabecula, is a consistent structure in the morphologic right ventricle and can be helpful as a landmark in situations where the ventricles may be ambiguous (i.e. in some forms of congenital heart disease).

The term "septomarginal" is descriptive since the muscle extends from the interventricular septum to the margin of the right ventricle, contacting/joining the base of the anterior tricuspid papillary muscle.  

The moderator band does not attach to a tricuspid valve, but acts as part of the electrical conduction pathway of the heart -- part of the right bundle branch.

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Case information

rID: 31559
Published: 16th Oct 2014
Last edited: 21st Apr 2020
System: Cardiac
Inclusion in quiz mode: Included

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