Septum secundum

Septum secundum
Septum secundum
	A labelled diagram of the developing heart, showing the relationship between the septum secundum (by the right atrium) and the septum primum (by the left atrium).
	Same heart as above, opened on right side. (Septum secundum visible in dark area at center top.)
Details
Carnegie stage	14
Days	33
Gives rise to	Atrial septum
Identifiers
Latin	septum secundum
	Anatomical terminology [edit on Wikidata]

The septum secundum is a muscular flap that is important in heart development. It is semilunar in shape, and grows downward from the upper wall of the atrium immediately to the right of the septum primum and ostium secundum. It is important in the closure of the foramen ovale after birth.

Structure

Development

At the end of the fifth week of development, the septum secundum grows from the upper wall of the primitive atrium.^[1] It grows to the right of the septum primum, which has already started growing.^[1] It grows down towards the septum intermedium formed from the endocardial cushions.^[1] Before birth, it does not fuse with the septum intermedium, leaving a gap to form the foramen ovale.^[1] Shortly after birth, it fuses with the septum primum to form the interatrial septum, and the foramen ovale is closed.^[1] The fossa ovalis denotes the free margin of the septum secundum after birth.

Clinical significance

Sometimes, the fusion of the septum secundum to the septum intermedium is incomplete, and the upper part of the foramen remains patent.^[2] This creates an atrial septal defect (ASD).^[2]

References

This article incorporates text in the public domain from page 512 of the 20th edition of Gray's Anatomy (1918)

^ ^a ^b ^c ^d ^e Belmont, John W. (2015-01-01), Moody, Sally A. (ed.), "Chapter 33 - Genetic and Developmental Basis of Congenital Cardiovascular Malformations", Principles of Developmental Genetics (Second Edition), Oxford: Academic Press, pp. 607–633, ISBN 978-0-12-405945-0, retrieved 2021-01-05
^ ^a ^b Carlson, Bruce M. (2014-01-01), "Development of the Heart", Reference Module in Biomedical Sciences, Elsevier, doi:10.1016/b978-0-12-801238-3.05460-x, ISBN 978-0-12-801238-3, retrieved 2021-01-05

External links

Embryology at Temple Heart98/heart97a/sld037
cardev-039—Embryo Images at University of North Carolina
Overview at edu.mt
MedEd at Loyola GrossAnatomy/thorax0/Heart_Development/Atria.html

[:1-1] Belmont, John W. (2015-01-01), Moody, Sally A. (ed.), "Chapter 33 - Genetic and Developmental Basis of Congenital Cardiovascular Malformations", Principles of Developmental Genetics (Second Edition), Oxford: Academic Press, pp. 607–633, ISBN 978-0-12-405945-0, retrieved 2021-01-05

[:0-2] Carlson, Bruce M. (2014-01-01), "Development of the Heart", Reference Module in Biomedical Sciences, Elsevier, doi:10.1016/b978-0-12-801238-3.05460-x, ISBN 978-0-12-801238-3, retrieved 2021-01-05

[1]

[2]