Left margin of heart

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Left margin of heart
Sternocostal surface of heart.
Heart seen from above.
Gray's	subject #138 528
Dorlands/Elsevier	m_04/12513824

The left margin of heart (or obtuse margin) is shorter than the right border of heart, full, and rounded: it is formed mainly by the left ventricle, but to a slight extent, above, by the left atrium.

It extends from a point in the second left intercostal space, about 2.5 mm. from the sternal margin, obliquely downward, with a convexity to the left, to the apex of the heart.

[edit] External links

• MedEd at Loyola medicine/pulmonar/cxr/atlas/silouhette2.htm

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e Anatomy of torso, cardiovascular system: heart Structures atria (interatrial septum, musculi pectinati) • ventricles (interventricular septum, trabeculae carneae, chordae tendinae, papillary muscle) • valves • cusps Regions base • apex • grooves (coronary/atrioventricular, interatrial, anterior interventricula, posterior interventricular) • surfaces (sternocostal, diaphragmatic) • borders (right, left) Right heart (vena cavae, coronary sinus) → right atrium (atrial appendage, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of the inferior vena cava, valve of the coronary sinus) → tricuspid valve → right ventricle (conus arteriosus, moderator band/septomarginal trabecula)  → pulmonary valve → (pulmonary artery and pulmonary circulation) Left heart (pulmonary veins) → left atrium (atrial appendage) → mitral valve → left ventricle → aortic valve (aortic sinus) → (aorta and systemic circulation) Layers pericardium: fibrous pericardium • serous pericardium (pericardial cavity, epicardium/visceral layer) • pericardial sinus myocardium • endocardium • cardiac skeleton (fibrous trigone, fibrous rings) Conduction system Cardiac pacemaker • SA node • AV node• bundle of His • Purkinje fibers