Difference between revisions of "Fossa ovalis (heart)"

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{{for|the fossa ovalis of the thigh|saphenous opening}}
{{Infobox anatomy
| Name        = Fossa ovalis
| Latin      = Fossa ovalis cordis
| Image      = Gray493.png
| Caption    = Heart viewed from the front, with [[right atrium]] and [[right ventricle]] opened. Fossa ovalis is labeled in the right atrium.
| Image2      =
| Caption2    =
| Precursor  = [[foramen ovale (heart)|Foramen ovale]]
| System      =
The '''fossa ovalis''' is a depression in the [[right atrium]] of the [[heart]], at the level of the [[interatrial septum]], the wall between right and [[left atrium]]. The fossa ovalis is the remnant of a thin fibrous sheet that covered the [[foramen ovale (heart)|foramen ovale]] during [[prenatal development|fetal]] development.
The '''fossa ovalis''' is a depression in the [[right atrium]] of the [[heart]], at the level of the [[interatrial septum]], the wall between right and [[left atrium]]. The fossa ovalis is the remnant of a thin fibrous sheet that covered the [[foramen ovale (heart)|foramen ovale]] during [[prenatal development|fetal]] development.
During fetal development, the foramen ovale allows blood to pass from the right atrium to the [[left atrium]], bypassing the nonfunctional fetal lungs while the fetus obtains its oxygen from the [[placenta]]. A flap of tissue called the [[septum primum]] acts as a valve over the foramen ovale during that time. After birth, the introduction of air into the lungs causes the pressure in the [[Pulmonary circulation|pulmonary circulatory]] system to drop. This change in pressure pushes the septum primum against the [[atrial septum]], closing the foramen.<ref name="patent foramen ovale guide">{{cite journal|last=Hara|first=H |author2=Virmani, R |author3=Ladich, E |author4=Mackey-Bojack, S |author5=Titus, J |author6=Reisman, M |author7=Gray, W |author8=Nakamura, M |author9=Mooney, M |author10=Poulose, A |author11=Schwartz, RS|title=Patent foramen ovale: current pathology, pathophysiology, and clinical status.|journal=Journal of the American College of Cardiology|date=Nov 1, 2005|volume=46|issue=9|pages=1768–76|pmid=16256883|doi=10.1016/j.jacc.2005.08.038}}<!--|accessdate=30 May 2012--></ref> The septum primum and atrial septum eventually fuse together to form a complete seal, leaving a depression called the fossa ovalis. By age two, about 75% of people have a completely sealed fossa ovalis. An unfused fossa ovalis is called a [[patent foramen ovale]]. Depending on the circumstances, a patent foramen ovale may be completely asymptomatic, or may require surgery.<ref name="patent foramen ovale guide" /> The '''limbus of fossa ovalis''' ('''annulus ovalis''') is the prominent oval margin of the fossa ovalis in the right atrium. It is most distinct above and at the sides of the fossa ovalis; below, it is deficient. A small slit-like valvular opening is occasionally found, at the upper margin of the fossa, leading upward beneath the limbus, into the [[left atrium]]; it is the remains of the fetal aperture the foramen ovale between the two [[Atrium (heart)|atria]].
Almost immediately after the infant is born, the foramen ovale and [[ductus arteriosus]] close. The major changes that are made by the body occur at the first breath (in the case of heart and lung functions) and up to weeks after birth (such as the liver's [[protein synthesis|enzyme synthesis]]). The foramen ovale becomes the fossa ovalis as the foramen closes while edge of the septum secundum in right atrium becomes anulus ovalis, so the depression beneath it becomes the fossa ovalis.<ref name="What is the Fossa Ovalis?">{{cite web|last=Johnson|first=Donna|title=What is the Fossa Ovalis?|url=http://www.wisegeek.com/what-is-the-fossa-ovalis.htm|accessdate=16 March 2012|publisher=Conjecture Corporation}}{{Unreliable medical source|date=May 2012}}</ref> This enables respiration and circulation independent from the mother's placenta.
With the child's first breath, the lung sends [[oxygenated blood]] to the left atrium. As a result, pressure in the left atrium is higher than that of the right, and the increased pressure holds the interatrial flap (which covers the foramen ovale) shut, therefore closing the foramen ovale as well.<ref name="What is the Fossa Ovalis?"/> In normal development, the closed foramen ovale fuses with the interatrial wall. During the first breath, vasoconstriction causes the ductus arterious to close, and during adult years, tissue occludes what once was the ductus arterious, creating the [[ligamentum arteriosum]].<ref name="Respiratory System">{{cite web|author=Dryden, Richard|title=Respiratory system|url=http://www.bionalogy.com/respiratory_system.htm|accessdate=16 April 2012}}</ref>
==Clinical significance==
[[Aneurysms]] can occur in adulthood if the foramen ovale is not closed correctly. An aneurysm happens when an artery becomes enlarged in a localized area due to weakening of the arterial wall.<ref>{{cite journal|last1=Shirani|first1=J.|last2=Zafari|first2=A.M.|last3=Roberts|first3=W.C.|title=Morphologic features of fossa ovalis membrane aneurysm in the adult and its clinical significance.|journal=Journal of the American College of Cardiology|date=August 1995|volume=26|issue=2|pages=466–71|pmid=7608452|doi=10.1016/0735-1097(95)80024-b}}</ref>
When this type of aneurysm occurs in the area of the fossa ovalis, an enlarged pouch is formed. This pouch can protrude into the right atrium or the left atrium. The cause of this aneurysm is the result of abnormal, increased pressure within the heart. Even if the foramen ovale does seal shut, an aneurysm may occur, usually on the side of the right atrium. If the aneurysm stretches too far, it can narrow the opening of the [[inferior vena cava]].<ref>{{cite journal|last1=Topaz|first1=O.|last2=Edwards|first2=J.E.|last3=Bojack-Mackey|first3=S|last4=Titus|first4=J.L.|title=Aneurysm of fossa ovalis in adults: a pathologic study|journal=Cardiovascular Pathology|date=Jul–Aug 2003|volume=12|issue=4|pages=219–25|pmid=12826292|doi=10.1016/s1054-8807(03)00041-3}}</ref> This type of aneurysm can be a result of [[atheroma|plaque]] build-up in the arteries from [[coronary heart disease]], as well as diseases of the [[aortic valve]] or [[mitral valve]]. Surgery may be useful in helping to cope with the aneurysm.
===Patent foramen ovale===
{{main|Patent foramen ovale}}
If the atrial septum does not close properly, it leads to a patent foramen ovale (PFO). This type of defect generally works like a flap valve, opening during certain conditions of increased pressure in the chest, such as during strain while having a bowel movement, cough, or sneeze. With enough pressure, blood may travel from the right atrium to the left. If there is a [[blood clot|clot]] in the right side of the heart, it can cross the PFO, enter the left atrium, and travel out of the heart and to the brain, causing a [[stroke]]. If the clot travels into a [[coronary artery]] it can cause a [[heart attack]].<ref>{{cite web|title= Patent Foramen Ovale|url=http://my.clevelandclinic.org/heart/disorders/congenital/pfo.aspx|accessdate=15 April 2012|publisher=The Cleveland Clinic}}</ref>
==See also==
* [[Fetal circulation]]
==External links==
* {{UMichAtlas|ht_rt_atrium}} – "Right atrium, internal structure, anterior view"
* [http://faculty.ucc.edu/biology-potter/Fetal_Blood_Vessels/sld015.htm Diagram]
* [http://www.lumen.lumc.edu/lumen/MedEd/GrossAnatomy/dissector/practical/thorax/thorax12.html Dissection photo]
{{Heart anatomy}}
{{Heart anatomy}}
{{Authority control}}
{{Authority control}}

Latest revision as of 02:18, 16 January 2020


The fossa ovalis is a depression in the right atrium of the heart, at the level of the interatrial septum, the wall between right and left atrium. The fossa ovalis is the remnant of a thin fibrous sheet that covered the foramen ovale during fetal development.


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