Atrioventricular septum

Atrioventricular septum
Interior of heart. (AV septum not labeled, but region is visible.)
Coronal cross section of heart. Note how the septum between the RA and LV becomes membranous.
Details
Identifiers
Latin	septum atrioventriculare
TA	A12.1.00.016
FMA	7136
*Anatomical terminology* [edit on Wikidata]

The atrioventricular septum is a septum of the heart between the right atrium (RA) and the left ventricle (LV).^[1]^[2]

Although the name "atrioventricular septum" implies any septum between an atrium and a ventricle, in practice the divisions from RA to RV and from LA to LV are mediated by valves, not by septa. Also, there is usually no communication between the LA and the RV.

Structure

It has a membranous and muscular part.^[3]

When considering only the membranous septum, it is also known as the "atrioventricular component of the membranous septum".^[4]

Development

It is formed by the union of the dorsal AV cushion and ventral AV cushion.^[5] This septum divides the atrioventricular canal.^[6]

Clinical relevance

In some cases, defects can be identified with an echocardiogram.^[7]

Incomplete formation of the endocardial cushions can lead to atrioventricular septal defects, such as an ostium primum defect.

References

↑ "Congenital Heart Disease - When Chambers and Valves Are in Normal Sequence and Position". Retrieved 2009-10-11.
↑ "Congenital Heart Disease". Retrieved 2009-10-11.
↑ "Yale: Congenital Heart Disease: AV septal defects". Retrieved 2009-10-11.
↑ Phelps CM, Mengshol S, Ivy DD (December 2008). "A curious isolated cystic lesion of the membranous atrioventricular septum". Cardiol Young 18 (6): 631–4. doi:10.1017/S104795110800276X. PMC 3118089. PMID 18950547.
↑ Fix, James D.; James D., PhD. Fix; Dudek, Ronald W. (2005). Embryology. Hagerstwon, MD: Lippincott Williams & Wilkins. p. 35. ISBN 0-7817-5726-6.
↑ Kirby, Margaret L. (2007). Cardiac development. Oxford [Oxfordshire]: Oxford University Press. p. 104. ISBN 0-19-517819-X.
↑ Croti UA, Braile DM, Hassem Sobrinho S, Godoy MF (March 2007). "Case 2/2007: left atrial isomerism in the defect of partial atrioventricular septum". Rev Bras Cir Cardiovasc 22 (1): 125–6. PMID 17992316.

External links

http://www.acc.org/membership/community/pediatric/opinion_apr03/Slide11.JPG

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) → 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 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

Blood supply

Coronary circulation

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