Moderator band

Muscle band in the right ventricle of the heart

Moderator band
Interior of right side of heart. (Septomarginal trabecula visible at bottom right, but not labeled.)
Details
Identifiers
Latin	trabecula septomarginalis
TA98	A12.1.02.020
TA2	4050
FMA	7272
Anatomical terminology [edit on Wikidata]

The moderator band (also known as septomarginal trabecula^[1]) is a band of cardiac muscle found in the right ventricle of the heart.^[2]^[3]^[4] It is well-marked in sheep and some other animals, including humans. It extends from the base of the anterior papillary muscle of the tricuspid valve to the ventricular septum.^[2]

Structure

The moderator band is located in the right ventricle.^[2]^[3] The moderator band connects the base of the anterior papillary muscles of the tricuspid valve to the ventricular septum.^[2]

Function

The moderator band is important because it carries part of the right bundle branch of the atrioventricular bundle of the conduction system of the heart to the anterior papillary muscle.^[1] This shortcut across the chamber of the ventricle ensures equal conduction time in the left and right ventricles, allowing for coordinated contraction of the anterior papillary muscle.^[1]

Clinical significance

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

History

From its attachments it was thought to prevent overdistension of the ventricle, and was named the "moderator band". It was first described by Leonardo da Vinci in his exploration of human anatomy.

Additional images

Location of the moderator band

References

^ ^a ^b ^c Whitaker, Robert H. (2014-08-01). "Anatomy of the heart". Medicine. Cardiovascular Medicine Part 1 of 4. 42 (8): 406–408. doi:10.1016/j.mpmed.2014.05.007. ISSN 1357-3039.
^ ^a ^b ^c ^d Rocha, H.; Eliziário, L. F. E.; Wafae, G. C.; Silva, N. C.; Ruiz, C. R.; Wafae, N. (2010-05-01). "Anatomy of the septomarginal trabecula in Landrace pig hearts". Morphologie. 94 (305): 26–29. doi:10.1016/j.morpho.2010.03.004. ISSN 1286-0115. PMID 20359929.
^ ^a ^b Kosiński, Adam; Nowiński, Janusz; Kozłowski, Dariusz; Piwko, Grzegorz; Kuta, Włodzimierz; Grzybiak, Marek (2007-09-10). "The crista supraventricularis in the human heart and its role in the morphogenesis of the septomarginal trabecula". Annals of Anatomy - Anatomischer Anzeiger. 189 (5): 447–456. doi:10.1016/j.aanat.2007.01.008. ISSN 0940-9602. PMID 17910398.
^ Drake, Richard L.; Vogl, Wayne; Mitchell, Adam W. M.; Gray, Henry (2024). "Thorax". Gray's anatomy for students (5nd ed.). Philadelphia, PA: Elsevier. p. 198. ISBN 978-0-323-93423-7.

External links

Videos and photos of moderator band
Photo of "septomarginal trabiculation" at acc.org
Photo with caption "moderator band" at tjc.edu
Sonogram

Anatomy of the heart

General

Surface

Internal

atria interatrial septum pectinate muscles terminal sulcus ventricles interventricular septum trabeculae carneae chordae tendineae papillary muscle valves cusps atrioventricular septum
cardiac skeleton intervenous tubercle

Chambers

Right heart	(venae cavae, coronary sinus) → right atrium (atrial appendage, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of inferior vena cava, valve of coronary sinus) → tricuspid valve → right ventricle (infundibulum, moderator band/septomarginal trabecula, crista supraventricularis), → pulmonary valve → (pulmonary artery and pulmonary circulation)
Left heart	(pulmonary veins) → left atrium (atrial appendage) → mitral valve → left ventricle → aortic valve (aortic sinus) → (aorta and systemic circulation)

Layers

Endocardium	heart valves
Myocardium	Conduction system cardiac pacemaker SA node Bachmann's bundle AV node bundle of His bundle branches Purkinje fibers
Pericardial cavity	pericardial sinus
Pericardium	fibrous pericardium sternopericardial ligaments serous pericardium epicardium/visceral layer fold of left vena cava