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.
Latinseptum atrioventriculare
Anatomical terminology

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.


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]


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.

See also


  1. ^ "Congenital Heart Disease - When Chambers and Valves Are in Normal Sequence and Position". Archived from the original on 2011-07-19. Retrieved 2009-10-11.
  2. ^ "Congenital Heart Disease". Archived from the original on 2009-08-28. Retrieved 2009-10-11.
  3. ^ "Yale: Congenital Heart Disease: AV septal defects". Archived from the original on 2009-06-07. Retrieved 2009-10-11.
  4. ^ 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.
  5. ^ Fix, James D.; James D., PhD. Fix; Dudek, Ronald W. (2005). Embryology. Hagerstwon, MD: Lippincott Williams & Wilkins. pp. 35. ISBN 0-7817-5726-6.
  6. ^ Kirby, Margaret L. (2007). Cardiac development. Oxford [Oxfordshire]: Oxford University Press. pp. 104. ISBN 978-0-19-517819-7.
  7. ^ 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. doi:10.1590/s0102-76382007000100023. PMID 17992316.