Foramen ovale (heart)

Foramen ovale (heart)
Foramen ovale (heart)
Foramen ovale.png
Sketch showing foramen ovale in a fetal heart. Red arrow shows blood from the inferior caval vein. HF: right atrium, VF: left atrium. HH og VH: right and left ventricle. The heart still has a common pulmonary vein (LV), instead of four.
Gray468.png
Heart of human embryo of about thirty-five days, opened on right side.
Gray's subject #135 512
MeSH Foramen+Ovale

In the fetal heart, the foramen ovale (also ostium secundum of Born or falx septi) allows blood to enter the left atrium from the right atrium. It is one of two fetal cardiac shunts, the other being the ductus arteriosus (which allows blood that still escapes to the right ventricle to bypass the pulmonary circulation). Another similar adaptation in the fetus is the ductus venosus. In most individuals, the foramen ovale (pronounced /fɒˈreɪmɨn oʊˈvæliː/) closes at birth. It later forms the fossa ovalis.

Contents

Development

The foramen ovale forms in the late fourth week of gestation. Initially the atria are separated from one another by the septum primum except for a small opening in the septum, the ostium primum. As the septum primum grows, the ostium primum narrows and eventually closes. Before it does so, bloodflow from the inferior vena cava wears down a portion of the septum primum, forming the ostium secundum. Some embryologists postulate that the ostium secundum may be formed through programmed cell death.[1]

The ostium secundum provides communication between the atria after the ostium primum closes completely. Subsequently, a second wall of tissue, the septum secundum, grows over the ostium secundum in the right atrium. Bloodflow then only passes from the right to left atrium by way of a small passageway in the septum secundum and then through the ostium secundum. This passageway is called the foramen ovale.

Closure

Normally this opening closes in the first three months following birth. When the lungs become functional at birth, the pulmonary pressure decreases and the left atrial pressure exceeds that of the right. This forces the septum primum against the septum secundum, functionally closing the foramen ovale. In time the septa eventually fuse, leaving a remnant of the foramen ovale, the fossa ovalis.

Clinical relevance

In about 30% of adults the foramen ovale does not close completely, but remains as a small patent foramen ovale.

PFO has long been studied because of its demonstrated role in some cases of paradoxical embolism. After exclusion of more common causes of stroke and TIA, transesophageal echocardiography should be considered in order to exclude cardiogenic foci of embolism. The presence of a patent foramen ovale should be considered as a possible cause of the cerebrovascular event, even though it may simply be an occasional finding in patients with cryptogenic stroke.

References

  1. ^ Sadler, Thomas W. (2004). Langman's Essential Medical Embryology. Lippincott Williams & Wilkins. ISBN 0781755719. 
  • Carlson, Bruce (2004). Human Embryology And Developmental Biology (3rd edition). Elsevier Mosby. ISBN 0-323-03649-X. 

External links


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Look at other dictionaries:

  • Foramen ovale — There are multiple structures in the human body with the name foramen ovale (plural: foramina ovalia; Latin for oval hole ): In the fetal heart, the foramen ovale (heart) is a shunt from the right atrium to left atrium. At the base of the skull,… …   Wikipedia

  • Foramen Ovale Perméable (FOP) — Foramen ovale perméable Le Foramen ovale perméable est un type d anomalie de la cloison située entre les deux oreillettes entraînant une communication entre ces deux dernières. Il est observée avec une grande fréquence et serait possiblement… …   Wikipédia en Français

  • Foramen ovale permeable — Foramen ovale perméable Le Foramen ovale perméable est un type d anomalie de la cloison située entre les deux oreillettes entraînant une communication entre ces deux dernières. Il est observée avec une grande fréquence et serait possiblement… …   Wikipédia en Français

  • foramen ovale — [ō vā′lē] n. the small, oval opening in the wall that separates the atria of the heart in a normal fetus: it allows blood to bypass the nonfunctioning fetal lungs until the time of birth when it gradually closes up * * * …   Universalium

  • foramen ovale — [ō vā′lē] n. the small, oval opening in the wall that separates the atria of the heart in a normal fetus: it allows blood to bypass the nonfunctioning fetal lungs until the time of birth when it gradually closes up …   English World dictionary

  • Foramen ovale perméable — Le Foramen ovale perméable est un type d anomalie de la cloison située entre les deux oreillettes entraînant une communication entre ces deux dernières. Il est observé avec une grande fréquence et serait possiblement impliquée dans diverses… …   Wikipédia en Français

  • foramen ovale cordis — [TA] foramen ovale of heart the aperture in the septum secundum of the fetal heart that provides a communication between the atria. Called also oval foramen of heart …   Medical dictionary

  • Foramen ovale — An oval opening between the two upper chambers of the heart (the atria) that is a normal feature of the fetal and neonatal (newborn) circulation. The foramen ovale normally closes on its own by 3 months of age. * * * foramen ova·le ō va (.)lē, vā …   Medical dictionary

  • foramen ovale — noun Etymology: New Latin, literally, oval opening Date: circa 1860 an opening in the septum between the two atria of the heart that is normally present only in the fetus …   New Collegiate Dictionary

  • foramen ovale — noun An opening in the septum between the right and left atria of the fetal heart …   Wiktionary

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