Atrioventricular cushions

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Atrioventricular cushions
Interior of dorsal half of heart from a human embryo of about thirty days.
Latin Tubera endocardiaca atrioventricularia
Gray's p.512
Carnegie stage 14
Days 27
Precursor Lateral plate mesoderm[1]
Gives rise to Septum intermedium
Code TE E5.

Atrioventricular cushions or endocardial cushions refers to a subset of cells in the primordial heart that play a vital role in proper heart septation.

They develop on the atrioventricular canal[2] and conotruncal region.[3]

During heart development, the heart starts out as a tube. As heart development continues this tube undergoes conformational changes and remodeling to eventually form the four-chambered heart. The endocardial cushions are a subset of cells found in the developing heart tube that will give rise to the heart's valves and septa critical to the proper formation of a four-chambered heart.

Clinical significance[edit]

A problem in endocardial cushion development or remodeling is thought to be associated with atrioventricular septal defect.


The endocardial cushions are thought to arise from a subset of endothelial cells that undergo endothelial to mesenchymal transition, a process whereby these cells break cell-to-cell contacts and migrate into the cardiac jelly (towards to interior of the heart tube). These migrated cells form the "swelling" seen in the heart tube that is termed endocardial cushions

Upon sectioning of the heart the atrioventricular cushions can be observed in the lumen of the atrial canal as two thickenings, one on its dorsal and another on its ventral wall. These thickenings or endocardial cushions will go on to fuse and remodel to eventually form the valves and septa of the mature adult heart.

See also[edit]


  1. ^ Maschhoff KL, Baldwin HS (2000). "Molecular determinants of neural crest migration". Am. J. Med. Genet. 97 (4): 280–8. doi:10.1002/1096-8628(200024)97:4<280::AID-AJMG1278>3.0.CO;2-N. PMID 11376439. 
  2. ^ "endocardial cushions" at Dorland's Medical Dictionary
  3. ^ Template:Langman's Medical Embryology

This article incorporates text from a public domain edition of Gray's Anatomy.

External links[edit]